Is it possible to (possibly through ReTuner) enable vampire interactions for teens and teen vampires, like in The Sims 4?

Possibly, but I think you will find that some of them are hard blocked by the game core. For the teen vamp performing the actions, you probably wouldn't like the results in many cases as there wouldn't be animations defined for these things, so the teen sims would stretch out and look totally malformed while performing them, depending on the actions you had in mind.

There may be a combo tuning/script mod with animations that unlocks these things, but that would have to come from another source. Perhaps our other members here can suggest one, if it exists, or you might post on the Where Can I Find? (WCIF) TS3 board at Mod The Sims.

I think this one unlocks teen interactions. It is by Puddingface, who has some other really nice mods over there.
https://modthesims.info/d/648599/enhanc ... 04-21.html

Thanks, I'll check it out.