For the QJ hand, you only calculated our foldequity and said it was +EV, but I don't understand why you didn't calculate our euity if we checked.
It's like saying openshoving AA is profitable. It is profitable, but probably more +EV to raise.
The fact that you are going to get a curiosity call when you take a bet check bet line makes it likely that you have implied odds when you hit a Q or J, since he is likely (which I don't think is good) going to lead a Kx OTR.
So doing some rough calculation, I though it was a pretty close spot to 2B or check back.
Its kind of a rough analogy given the situational differences. We can certainly run the calculations, but the problem with figuring out the EV of checking back is it involves a significant amount of assumptions that could sway the EV one way or the other. To name a few, we don't know if villain folds kx on the river and if so at what frequency (unlikely but possible). We certainly have the potential to get called by more pocket pairs, but again, at what frequency. Also, if we check are we bluffing some rivers? If so we have to figure out what ones and what frequency we expect villain to fold on those various rivers.
Additionally, we have 12.2% equity when called on the turn, but that doesn't mean that 12.2% of the time we can confidently value bet the river (in actuality our equity would be higher if we check, given that he can have more weaker hands that he folds if we bet the turn). Our Q and J outs likely will not be value bet by us. So we have 4 tens that we will value bet. One of those completes a flush draw, which may or may not change villains calling frequency. So lets say he calls on the Ts 50% of the time, so we really will be able to confidently value the river 7.6% of the time. Meaning that 92.4% of the time we will either check back, thin value bet (unadvisable vs an unknown), or bluff. I would also argue that our implied odds are the same, if not better, with a turn bet, given that villain calls the turn with a stronger range/range that is getting stubborn.
Given that we have a known +EV turn bet, plus when we get to the river our chance of improving is similar (although admittedly less than if we check the turn), our implied odds are very similar (if not better), and the amount of unknowns makes calculating the EV difficult, I think opting for a turn bet is better overall. However, this isn't to say that a bet-check-bet line is not good or +EV. It is a viable option and may be close, as you point out. I would assume that betting the turn is better though.