How long does it take to receive the $7500 bonus after ioe?

I believe I got mine the next pay period after finishing my type checkride.

Other regionals have similar provisions. It's good for pilots...

If they ever find themselves in need of a job, they can come back, suck up FO pay for a couple or few years and then be back at six figures.

Especially good for guys who got stuck due to industry dynamics and now cannot afford to risk going to a major and flunking out. This allows/enables those folks to attempt to move on without risking financial catastrophe.

Good for the company because it encourages senior (ie expensive) pilots to move one.

I would even take it one step further...since the whole point of the regional system for most pilots is (or was originally) to get experience and move on, I would allow pilots to return with seniority for 4-6 months. That way there is no downside to attempting to move to a major. Kind of like insurance, small cost to the group as a whole and very few folks would ever need to exercise that option, but if YOU happened to be that guy who the sim instructor didn't like the part of your hair...

I believe XJET already has something like that in place... maybe 2-3 month but the same idea.

I got mine about a month out of IOE, but had to call recruiting to check on it. They emailed back right away and said my bonus would be on the next pay period.
Mine was for previous 135 experience and Lear SIC type, but if you have just 135 experience, that'll work.

Will November classes for the E175 consist of all FO's, or will there be Capt upgrades/transitions as well? If it's all FO's then will some FO's be sitting LHS for the sim?

It will be a mixed class. If there are more FOs than captains, then there will be some FO/FO pairs and some FOs will sit in the left seat for half of the sim time.

Ok thanks .. and FOs will also get a PIC type rating regardless of seating arrangements?

Of course. Everyone gets pic types.

PIC type ratings are required for all 121 pilots.