No. You just have to see them all but seeing them in the Battle Tower doesn't count as seeing them for some reason, and don't get in your pokedex.
... you beat it.After that, you can catch the remaining legendaries and complete your national dex.(Dum answer)
catch every Pokemon or get all the Pokemon you have to lv 100 or trade all of the good Pokemon to a different game and start over
I'm not sure if you can catch Eevee in Pokemon pearl but you get it as a gift from Bebe in Hearthrome City after you get the national dex.
no
Catch all the Pokemon.
Catch all the Pokemon in the game
you can catch pinsir its uncommon but on route 229 which u can only get to if you complete the Pokemon league
you have to complete the first pokedex
you can't but you can trade Pokemon at the pal park
get the national pokedex and talk to Bebe after seeing 151 Pokemon
upgrade to the national dex and see and catch every Pokemon
start again