Do you still need to separate the EXP from the health bar? I was looking through my notes, but I couldn't find anything on the HUD. I think the notes for that might be on my old computer, which I used to hack Zelda II back then. Anyway, I opened a clean rom and did some testing to re-create the HUD I made in Shadow of Night, and I remembered how I separated the exp from the health bar. (something you needed help with, right?)
Well, here is a screenshot to help me explain:

There are 3 parts to the exp counter. Part 1 and 2 are the green highlighted portion, and part 3 is the red. The yellow highlighted portion is what you see in game, and purple is what I did for Shadow of Night.
Part 1 is at 0x1655.20 6E 10 F4 F4 F4 F4 F4 F4 F4 F4 D0 D0 D0 D0 CE D0 D0 D0
This line of code is the entire green portion of the screenshot. 6E is the position in the HUD, and 10 (16) is the length of tiles. So without having any digits in the exp counter, you would only see 0000/000. Those are static tiles.
Part 2 is the actual position of each digit within the above range of tiles.0x1769 - Position of tens digit for current xp value.
0x176E - Position of hundreds digit for current xp value.
0x1773 - Position of thousands digits for current xp value.
0x1777 - Position of ones digit for current xp value.
0x1789 - Position of tens digit in required xp value.
0x178E - Position of hundreds digit in required xp value.
0x1793 - Position of thousands digit in required xp value.
The tens digit in the required exp is the LAST digit within the counter. There is no ones digit since it is never used. If you try to move a digit outside of the counter's range of tiles, it won't be visible.
Part 3 is at 0x1D101.20 7A 05 CE D0 D0 D0 D0
This line of code is the red potion of the screenshot. It is a static string of tiles, and its only purpose is to have a ones digit in the required exp. It sits behind the actual exp counter, and looks like this /0000 in game. 7A is the position, and 05 is the length of tiles.
What I did for Shadow of Night is the purple highlighted area in the screenshot. In that hack, I never used the ones digit OR tens digit for required exp. I sacrificed the tens digit by moving it out of Part 1's available range of 10 (16) tiles.
You probably don't want to do that, since Zelda II uses the tens digit for required exp, so your only option is to relocate the data in Part 1, and extend its range of tiles to 11 (17). Then you could freely moves all digits of the counter one space over.
As for the white tile in the magic meter, if I remember correctly, all I did was open Tile Layer Pro and moved the actual white square up one space. It made the boss health bars have an "empty" space between their remaining red bars and the white bars. It wasn't too big of a deal so I just left it, ha ha. I'm pretty sure that's how I did that, but I'll check to make sure. There is definitely a better way to do that.