Except for a couple of things you overlooked:
1. The age for universal access is 17 (16 for restricted access - celebrity gossip). Pedophiles aren't interested in mature teenagers. They are sexually attracted towards children (i.e. <13). This is why they are called pedophiles. Yes, I've seen the drawings but this just isn't the type of environment that young children would gravitate to.
2. I am assuming that when you are referring to "Groomers" you are referring to people who would try to troll other forum members sexually & try to hoodwink them into things such as sending nude pics of themselves. Grooming of this sort is more based on gullibility than it is on age. Is it possible that we could run into "
764 types" here trying to engage in "grooming"? Yes I am sure it is but it is much more likely on channels such as Discord or Telegram than here.
3.

is much more of a concern because not only has she repeatedly been obsessed with coming back on multiple sock puppets, she has shown a tendency to carry this IRL (i.e. calling my sister, harassing the company I work with, wanting to get my licensed revoked, expressing a desire that I should have somehow be "punished"(locked up, chemically castrated and so forth).
None of the behaviors that I have mentioned about

have been have observed with Bittersweet Symphony. I'm, not saying that drawing armless and legless drawings on DeviantArt isn't going to raise eyebrows, but if I am concerned about genuine threats by unbalanced people, it's probably better to go on concrete evidence rather than speculation.