I was replaying Fire Red last night, and got to the Five Island to grab the Togepi Egg. I've realized something. The old man who gives Red the Togepi Egg might be Mr. Pokémon from G/S/C/HG/SS.
The old man states that he received the egg that he gives Red in FR/LG while he was travelling. 3 years later, he moved to Johto. While giving the Egg to Gold, he states: "A friend of mine from Ecruteak gave it to me. I bet you can't find this kind of Egg in Johto."
It may be a dumb theory but it's fun to think that since FR/LG wrapped up some things for the next gen (for example why Lorelei left Elite 4, in FR/LG it's stated that she felt some remorse leaving her hometown unprotected in the Four Island after the Rocket incident), so it's fun to think that maybe Mr. Pokémon was around in Kanto and in the islands.
by kennykilled