I'm guessing that his intelligence quotient is in the bright (but not genius) range (115-135) for a number of reasons:
1. his mind would become sharpened and hyper-vigilant due to his stressful, dangerous lifestyle
2. it seems that he knew a fair amount of both French and Russian. and he might have taught himself what he did know.
3. there is a tremendous amount of fantasy and imagination that went into his personas and his methods. he seems more the organized offender with an elaborate imagination than the disorganized offender.
4. while his online presence might create a sense of idiocy in some regards, it seems to have mostly been smoke and mirrors so our assessment of his intellect (via grammar and sentence structure) should not be based directly off these online writings
5. his writing reflects that he lacks higher education but it says almost nothing about his fluid intellect
6. he doesn't look dumb. i realize this is a vague point but mentally challenged people don't have that kind of poise. neither am I saying that he's got grace. he just doesn't look like an imbecile.
7. he traveled the world to some degree (yes, he doctored some travel photos but not all) and explored many alternate lifestyle choices, which seems to betray a curiosity and independence that would allow for higher intellect.
8. supposedly he was computer savvy enough to use proxies and the deep web. sure, anyone could use them but your average person is usually not going to be that aware of these things because of it being challenging to navigate initially.
The things that I believe prevented him from having a genius iq are a one-track obsessiveness, lack of an environment that would have nurtured his intellect rather than simply heightening his survival skills, emotional rigidity that may or may not have resulted from abuse, and a preference for self-indulgence over learning. Further, he wasn't able to escape the lifestyle that was crushing him; he simply adapted to it and let it warp him whereas someone smarter would have in time realized that there were other options. Drugs might also have played a part though I think the role of drugs in limiting intellect is often overstated.
As for his dignity and compassion and every other virtue, he gets a big fat zero...no, he gets a negative value.
That makes sense....if his IQ was that low he wouldn't even comprehend what he was cut and pasting.