Any time it looks like a pig is trying to get back to its feet, I put another shot into, now. Any time I am not sure about how good the shot was, I put another shot into the hog, now. Any time the hog doesn't quiet down and go still in what I think is a reasonable amount of time, I put another shot into it, now. These are all from lessons learned in the field, LOL.
I would rather spend a few bucks on extra ammo to confirm a hog is down than to spend 2-4 hours (and sometimes a second trip back the next day which costs a lot more in fuel) looking for a likely mortally wounded hog that is undoubtedly dead somewhere in the local area. Ammo is cheap by comparison to time and effort spent searching.
However, the only real mistake I think you made was letting him get up that last time where you weren't ready to shoot him again. You were dinking with you light and zoom and he started moving out of the image and into the brush and you didn't pop him. That is just one of those lessons your learn from. Everything else looked like you are attempting to do what was right.
I agree. He is undoubtedly dead.