It is OK and common for those rollers to fall out of the pinion bearing cage. Simply dry the cage and rollers, then coat the inside of the cage with Vaseline and place all the needle/rollers back in place.

Well, you have a thrust bearing underneath that pinion bearing, along with a needle bearing just below the upper seal that you don’t want to rust with water based cleaners. There might be metal shavings in that thrust bearing too, you won’t really be able to tell without removing the pinion bearing to get at it.
I dunno buddy, you might be better off looking for a decent used gearcase.