Since this is the Speculation/Idea thread...
I speculate that Red will have a new team in HG/SS, since his team in G/S/C was supposedly based on Generation I as a whole, it would be logical to think that his team would be based on Generation III as a whole. Though that would screw up things, seeing as the main part of Generation III is Hoenn Pokemon, I believe that Red would receive a completely new team all together. I speculate that he will have a Kanto starter, two fire/water/grass Pokemon that act as substitutes for his starter, a random Pokemon, and then Espeon and Snorlax. Green would retain his post E4 team in FR/LG, meaning he would have a Kanto starter, then the 2 Exeguttor/Arcanine/Gyarados substitutes, Alakazam, Tyranitar, and then Heracross. If Blue (or "Leaf" as people refer to as) appears in the game, she would have a Kanto starter, 2 Fire/Water/Grass substitutes, and then 3 random Pokemon.
I'm only saying this because it doesn't seem reasonable for Red to keep his Generation I based team, and logically they would base it off Generation III, but there was no "Yellow" in Gen III, so it would be stupid for him to have a Pikachu.