Hey, that's why we have a glossary on this forum, so everyone knows what a certain word means when used on this site. Tulpa as a word is the most difficult one of course, but I'll pull numbers out of my ass and say majority here right now seems to think of tulpas as sapient or seemignly sapient enough to call them sapient beings pretty separate from you. Or something.
I'm pretty annoyed when people think that roleplaying characters are tulpas and call their roleplaying characters as such, even though the "tulpas" are always consciously parroted and puppeted. All day erry day and they're not even trying to hide it. Anyone doing that on my watch will, like, I dunno. Get an imaginary drink thrown in their face or something. It feels like lying to the rest until they actually tell you "oh, you mean my tulpa should be moving and talking on their own?". Such a let down.
I'd say an imaginary friend could be a tulpa and you could refer to your imaginary friend as a tulpa. But in my eyes, imaginary friend doesn't necessarily imply "sapience", while tulpa does. So a roleplaying character you think of as your "tulpa" might very well fit the imaginary friend category even if it doesn't fit the tulpa category. Basically, imaginary friend is a much broader category that includes tulpas and of course your imaginary friend could develop into a tupper. But it wouldn't be wrong to say a tulpa is an imaginary friend, just... Very broad definition.
You might want to write more about that level thing of yours, Fede. I heard about it previously ages ago and I dunno, maybe you'd like to flex your writing muscles. Sure, it's probably not something people would adopt (look at my level 69 tupra guise), but it's always interesting to hear what other people think. That's why the forums exist, after all.