Hey everyone, I've seen this topic and decided to join in. I'm loving the new improvement of Pokemon Yellow for the NES, I've wanted to mention that I've started uploading some of the remixed tracks on my YouTube channel.
I even discovered another YouTube user named Koh1dfs who has been uploading some videos of Pokemon Yellow for the NES aswell, but just the Chinese version. By watching a few of his videos, I managed to discover how to get some of the other legendary Pokemon.
Here's a list of the Legendary Pokemon locations, a few of them are still in their same locations like in R/B/Y versions.
*Articuno - Seafoam Islands Lvl 50
*Zapdos - Power Plant Lvl 50
*Moltres - Pokemon Mansion (Cinnabar Island) Lvl 50 (RE)
*Mewtwo - Cerulean Cave Lvl 70
*Mew - Celadon City Lvl 80 (Here's the video of getting Mew, you'll need to collect all 150 Pokemon including the G/S/C legendaries: https://www.youtube.com/watch?v=Ly8ZTu7MjAE
*Raikou - Secret Island/Navel Rock Lvl 50 (RE)
*Entei - Victory Road Lvl 50 (RE)
*Suicune - Route 21 Lvl 50 (RE)
*Lugia - Route 1 (Few multiples can be found at Lvl 10) and Secret Island/Navel Rock Lvl 70
*Ho-Oh - Secret Island/Navel Rock Lvl 70 (Another video of getting to Ho-Oh: https://www.youtube.com/watch?v=88h6Y-690Qk
RE obviously means random encounter, I put that there so most of you are aware that you'll only get to encounter these Pokemon once so be prepared, it's your only chance in the game.
I still haven't found out where Kyogre, Groudon and Rayquaza are, I've tried searching around most areas around Kanto but no luck yet. And if you were also wondering how to get to Navel Rock/Secret Island (where Ho-Oh is), you'd have to beat the Elite Four again after defeating/catching Mewtwo (I was wondering what Lorelei was saying when I came out of Cerulean Cave).
You're battling the E4 again (each person now has 6 Pokemon each) and instead of Gary, Jessie and James of TR are now the new champions (they still have Meowth, Arbok and Weezing, and in addition the final evolutions of the starters). After defeating the E4, go to the building in Celadon City (the door on the right where you get Fly) and battle the trainer in the center of the room (he looks like Brendan). After you defeat him, he'll let you go to Navel Rock, also his team consists of the legendary dogs and R/S/E legendaries.
And apparently Koh1dfs said that you can also catch Hitmonlee, Hitmonchan, Lapras, Omanyte, Kabuto and Aerodactyl at Navel Rock.