Wow, Yellow Forest is bigger than I expected!
A few more questions though:
1) Were you planning to incorporate the Kimono Girl appearances around the map from HG/SS? Culminating in their event for Ho-Oh later in the game?
2) Once you catch Celebi (presumably by taking the GS Ball to Ivy, then Kurt, then visiting Azalea Forest), were you thinking of including any other time travel sequences? The ones that were included in HG/SS were really awesome for helping to explain a few things and providing an awesome backstory, but I can't help feeling as though there's one more rather dramatic event that the player never got to see: The eruption of the Cinnebar Volcano. I'm not sure how much setup Mateo plans to put for this in Red++, but maybe an event could be scripted to have the player go back with Celebi, evacuate all the residents of Cinnebar by talking to them all, then visiting the volcano to discover what caused it or something? I dunno exactly, but it could be something to consider.
3) Kind of related to the last point. As far as I remember, the room in which Giovanni can be found in Tohjo falls can't actually be visited by exploring the cave normally. Would it be possible to include a way to get into this room and discover the radio still there, or maybe a Team Rocket-themed item on the floor? Or a mysterious unsigned letter addressed to Silver apologising for past mistakes? The first time the player goes through here to get to the Elite Four, the Celebi time travel event won't have happened yet. Therefore, it could be foreshadowing for players unfamiliar with this sidequest, and provides a recognizable room once it does happen.