Ah! That's interesting, especially since it's categorized under the items. Clever that they did that.
Yeah, it looks like the items you find by searching use the "[ME] discovers the [INV]." text, and the items you get from chests use the "Fortune smiles upon thee, [ME].&Thou hast found the [INV].%" text. The items you get from talking to people don't use any text at all

. There's some more cleverness in store for you if/when you start editing the title screen/end credits graphics

.
I tested this out in the translation, and it shouldn't be a problem since I didn't get any extra "s" characters in the text. My HP depletion text still reads "puntos". Perhaps the control code just looks for the word "Points"?
No, both "[PNT]" and "[XP]" print out extra text that doesn't show up there in the text dump. As long as you're not using "[PNT]" in your text, that part should be fine, but if you're using "[XP]", you'll still see "Before reaching thy next level of experience thou must gain 1 Point" / "2 Points" when talking to the King. The easiest way around that is to use "[NUM]", but if you do want different text for 1 vs. more than 1, the game is already set up to do that for those 2 control codes, so it shouldn't be too much more work to just change that text a bit.
My only qualm so far is with the formatting.
Ah, an easy problem, the best kind to have

. In the Trace Logger window, under Log Options, there's a "To the left from disassembly" checkbox (beside the "Log Processor status flags" checkbox it refers to) that controls that. Which one is best depends on the situation and your personal preference - try them both and choose!
EDIT: Looking through the trace log file, I (think I) followed the trail to this:
Congratulations, that is indeed the "T" in "TALK"! If you keep following the log further back, you'll eventually reach the code that starts reading that string (in this particular case, that's when Y=#$00, though the same can't be said in general):
$A1E6:B1 9F LDA ($9F),Y @ $B054 = #$80 A:B0 X:00 Y:00 S:F0 P:nvUBdIZc
And that's where things start to get interesting. Dragon Warrior's menu strings start with between 4 and 7 bytes that specify some of the menu window's properties, such as how many lines to print and how many characters wide the window is, and then continue until that many lines of text have been read. So, finding the end of each string is a little bit complicated. Fortunately, Dragon Warrior doesn't seem to waste any bytes in between strings and the final string is immediately followed by code (if you keep the Code/Data Logger open while you play through the game, it will eventually become pretty good at telling you what bytes are code and what bytes are data), so one way you can tackle the problem is to just dump the entire block from 0x6FC0-0x752C and match that up with the pointer table at 0x6F7C-0x6FBF, which I hear Pointer Tables is pretty good at. The corresponding Atlas insert script looks like this (I've kept the window setup bytes as raw hex to make it clear that they are not text and should not be treated as such during insertion):
#JMP($6FC0, $752C)
#W16($6F7C)
<$01><$06><$08><$21><$89><$B0><$88>LV<$82><$A0>HP<$81><$90>MP<$81><$94>G<$98>E<$A8>
#W16($6F7E)
<$21><$0B><$14><$35><$88><$85>NAME:<$B1><$80><$86>STRENGTH:<$D8><$80><$87>AGILITY:<$D9><$80><$84>MAXIMUM<$81>HP:<$DC><$80><$84>MAXIMUM<$81>MP:<$DD><$80><$82>ATTACK<$81>POWER:<$DA><$80><$81>DEFENSE<$81>POWER:<$DB><$80><$82>WEAPON:<$B8><$87><$83><$B8><$83>ARMOR:<$B9><$87><$83><$B9><$82>SHIELD:<$BA><$87><$83><$BA>
#W16($6F80)
<$01><$05><$18><$92><$88><$80><$80><$80><$80>
#W16($6F82)
<$80><$05><$10><$16><$08><$21><$8B>COMMAND<$88><$81>TALK<$84>SPELL<$81>STATUS<$82>ITEM<$80><$81>STAIRS<$82>DOOR<$80><$81>SEARCH<$82>TAKE<$80>
#W16($6F84)
<$80><$03><$10><$16><$08><$21><$8B>COMMAND<$88><$81>FIGHT<$83>SPELL<$81>RUN<$85>ITEM<$80>
#W16($6F86)
#W16($6F88)
<$80><$0B><$0C><$29><$00><$21><$8B>SPELL<$88><$D6><$81><$C0><$E8><$E9>
#W16($6F8A)
<$A0><$0B><$0C><$39><$00><$11><$88><$D4><$81><$BB><$82><$BB><$E8><$E9>
#W16($6F8C)
<$A0><$08><$12><$25><$00><$11><$88><$D5><$81><$BC><$81><$C8><$82><$BC><$80><$E8><$E9>
#W16($6F8E)
<$80><$03><$08><$25><$00><$21><$88><$81>YES<$80><$81>NO<$80>
#W16($6F90)
<$80><$03><$08><$25><$00><$21><$88><$81>BUY<$80><$81>SELL<$80>
#W16($6F92)
<$01><$07><$18><$52><$88><$81>A<$81>B<$81>C<$81>D<$81>E<$81>F<$81>G<$81>H<$81>I<$81>J<$81>K<$81>L<$81>M<$81>N<$81>O<$81>P<$81>Q<$81>R<$81>S<$81>T<$81>U<$81>V<$81>W<$81>X<$81>Y<$81>Z<$81>-<$81>}<$81>!<$81>?<$81>(<$81>)<$80><$81>a<$81>b<$81>c<$81>d<$81>e<$81>f<$81>g<$81>h<$81>i<$81>j<$81>k<$81>l<$81>m<$81>n<$81>o<$81>p<$81>q<$81>r<$81>s<$81>t<$81>u<$81>v<$81>w<$81>x<$81>y<$81>z<$81>,<$81>.<$81>BACK<$82>END
#W16($6F94)
<$A1><$07><$12><$74><$00><$86><$88><$81>Which<$81>Message<$80><$80><$81>Speed<$81>Do<$81>You<$80><$80><$81>Want<$81>To<$81>Use?<$80><$80><$80><$86>FAST<$80><$80><$86>NORMAL<$80><$80><$86>SLOW<$80>
#W16($6F96)
<$01><$02><$14><$73><$88><$81>INPUT<$81>YOUR<$81>NAME!<$80>
#W16($6F98)
<$01><$03><$0C><$35><$8B>NAME<$88><$81>********<$80>
#W16($6F9A)
<$81><$04><$18><$42><$00><$21><$88><$81>CONTINUE<$81>A<$81>QUEST<$80><$81>CHANGE<$81>MESSAGE<$81>SPEED<$80><$81>ERASE<$81>A<$81>QUEST<$80>
#W16($6F9C)
<$81><$06><$18><$42><$00><$21><$88><$81>CONTINUE<$81>A<$81>QUEST<$80><$81>CHANGE<$81>MESSAGE<$81>SPEED<$80><$81>BEGIN<$81>A<$81>NEW<$81>QUEST<$80><$81>COPY<$81>A<$81>QUEST<$80><$81>ERASE<$81>A<$81>QUEST<$80>
#W16($6F9E)
<$81><$02><$18><$42><$00><$21><$88><$81>BEGIN<$81>A<$81>NEW<$81>QUEST<$80>
#W16($6FA0)
<$81><$02><$14><$95><$00><$21><$88><$81>ADVENTURE<$81>LOG<$81>1<$80>
#W16($6FA2)
<$81><$02><$14><$95><$00><$21><$88><$81>ADVENTURE<$81>LOG<$81>2<$80>
#W16($6FA4)
<$81><$03><$14><$95><$00><$21><$88><$81>ADVENTURE<$81>LOG<$81>1<$80><$81>ADVENTURE<$81>LOG<$81>2<$80>
#W16($6FA6)
<$81><$02><$14><$95><$00><$21><$88><$81>ADVENTURE<$81>LOG<$81>3<$80>
#W16($6FA8)
<$81><$03><$14><$95><$00><$21><$88><$81>ADVENTURE<$81>LOG<$81>1<$80><$81>ADVENTURE<$81>LOG<$81>3<$80>
#W16($6FAA)
<$81><$03><$14><$95><$00><$21><$88><$81>ADVENTURE<$81>LOG<$81>2<$80><$81>ADVENTURE<$81>LOG<$81>3<$80>
#W16($6FAC)
<$81><$04><$14><$95><$00><$21><$88><$81>ADVENTURE<$81>LOG<$81>1<$80><$81>ADVENTURE<$81>LOG<$81>2<$80><$81>ADVENTURE<$81>LOG<$81>3<$80>
#W16($6FAE)
<$81><$02><$18><$63><$00><$21><$88><$81>ADVENTURE<$81>LOG<$81>1:<$B5><$80>
#W16($6FB0)
<$81><$02><$18><$63><$00><$21><$88><$81>ADVENTURE<$81>LOG<$81>2:<$B6><$80>
#W16($6FB2)
<$81><$03><$18><$63><$00><$21><$88><$81>ADVENTURE<$81>LOG<$81>1:<$B5><$80><$81>ADVENTURE<$81>LOG<$81>2:<$B6><$80>
#W16($6FB4)
<$81><$02><$18><$63><$00><$21><$88><$81>ADVENTURE<$81>LOG<$81>3:<$B7><$80>
#W16($6FB6)
<$81><$03><$18><$63><$00><$21><$88><$81>ADVENTURE<$81>LOG<$81>1:<$B5><$80><$81>ADVENTURE<$81>LOG<$81>3:<$B7><$80>
#W16($6FB8)
<$81><$03><$18><$63><$00><$21><$88><$81>ADVENTURE<$81>LOG<$81>2:<$B6><$80><$81>ADVENTURE<$81>LOG<$81>3:<$B7><$80>
#W16($6FBA)
<$81><$04><$18><$63><$00><$21><$88><$81>ADVENTURE<$81>LOG<$81>1:<$B5><$80><$81>ADVENTURE<$81>LOG<$81>2:<$B6><$80><$81>ADVENTURE<$81>LOG<$81>3:<$B7><$80>
#W16($6FBC)
<$01><$06><$14><$73><$88><$81><$B4><$80><$81>LEVEL<$82><$A1><$80><$81>Do<$81>You<$81>Want<$81>To<$80><$81>Erase<$81>This<$80><$81>Character?<$80>
#W16($6FBE)
<$80><$03><$08><$3A><$00><$21><$88><$81>YES<$80><$81>NO<$80>
A quick Google search yields that BPL means "Branch on Result Plus" (whatever the heck that means).
When you think of a byte as being a
2's complement integer, it's positive (Plus) when the high bit is 0 and negative (Minus) otherwise, so BPL means "go to this address if the negative processor flag is not set"; LDA updates the negative and zero flags based on the value it loads, so this boils down to "go to $A301 if the byte we just loaded is positive". The "negative" bytes with values >= #$80 get chopped up into a 4-bit index into a function jump table and a 3-bit parameter to the function that gets called; you'll be interested in at least #$80 (new line) and #$81 - #$87 (print 1 to 7 spaces).