On the rebaptism thing, in our denomination, it's done on occasion. (Southern Baptist here) Usually for someone who made a profession of faith and was baptized, but then later questioned if the profession was sincere. Baptism isn't in any way tied to your salvation in that you have to be baptized the "right way" to be saved, nor is it a method of confession of sins for the end goal of absolution. Instead, it is an outward expression of your profession of faith. If you feel that when you were baptized the first time you weren't actually saved and therefore your profession of faith was invalid, I would understand feeling the need to get baptized again now that you are.
This is all something that you should go over with a spiritual mentor - like your FIL pastor. DO NOT tell him about the adultery, but your salvation story and baptism would be fine. As for being pressured to serve in church leadership, you can simply say that you don't feel that God is calling you to that role at this time. If you go to him with the confession that you are questioning your salvation, that will probably get him off your back for a while about serving.