Everything that you described is perfectly normal, and there are lots of posts on the forum regarding the infamous "belch"! As for the turkey, just do the brine and you will be fine. I brine all poultry, and for turkey, I would give it at least 6 hours or preferably overnight. I smoked a whole chicken (7#) yesterday after brining over night and rubbed down first thing in the morning. The cavity of the chicken (or turkey for you) retains a lot of moisture and the end product is a very moist bird.