You can keep them as Tangela and Oddish/Gloom. They shouldn't be past level 10-30, really. XD
For Tangrowth, I am aiming for Double Powder. Sleep, Stun, Power Whip, and EQ.
For Bellossom, I am aiming for Sunlight. Sunny Day, Leaf Storm, Sleep Powder, and HP Fire.
So if they are naturally learning those moves (like powders) in their early levels, please teach it to them. I do have Heart Scales, though.. Their egg moves are not necessary for their sets.
I'm so happy that I took so many APs and got college transfer credit. <3