Believe it or not I have already soloed Wattson with an Electrike. Needless to say it was a huge pain in the *** but it happened. Also I personally hate Manectric, so I won't accept that, sorry.
Iron Man: Aron (can evolve freely, but must defeat two Pokemon from two different Gym Leaders before it may learn any TM/HM moves)
The Hulk: Makuhita (must get hit by Swagger and still defeat the opponent to evolve)
Hawkeye: Taillow (Can't learn TM/HM moves until 2 bosses soloed)