Well Scep is more he thinks the world is a maze, and wants cake. But also learned that flesh is tasty. Also he just does need to eat pokemon because Rattatas are omnivores. And I hope for pratical purposes that I change the team. I'd much prefer Fearow, or Dordio for my flier, Rattata kinda just weak, Pcebro's the only one I can see keeping based on stats.
So persumably I'll get a route 3 catch, replace something with Magikarp, and something with the Mt.Moon catch. That should give you quite a few catchs to change a personality.
I think scep is cool enough to be worth keeping around until sometime after Mt. Moon. I mean, other than geodude mt moon doesn't offer much unless you switch Pestilence out for a Paras. And, I'm not sure on this but does Magikarp count as the one mon you get from route 4? I'd just catch one when you get the old rod, prior to that training him seems like a colossal pain in the ass.
Personally, I feel Biolante, Spearow, Pcebro, Scep, Pestilance/Paras, and geodude are good. Unless you get a zubat, in which case 5 is probably good.
Girl, pack a sandwich before our date, cuz you know I'm gonna ask you for one later...