You will do IOE in the 200 OR 700/900 then OOE (Other Operating Experience) on the variant you didn't do IOE on. Then you're good to fly all 3 variants. The 700 lands very different from the 200. It's fun to go back and forth between the types. It keeps you on your game. IAH is a 700 only base. If for whatever reason you did IOE on the 200, and didn't get OOE done on the 700 for months, but got awarded IAH as a domicile your first 700 trip would be with an LCA to get your OOE done.