Wow! Quite a night. First of all, it happened, treat it like a learning experience, and move on to the next game. All of us have some ugly ones under our belt along the way and add some to it every now and again. The best thing you can do is figure out "why" and then drop it. Next time out it'll go better.
How was he pregame? It sounds like there was some ball watching going on. As far as the T situation, sounds like a good old fashioned goatf#@k, which in my area is one step beyond the cluster f#@k.
How was your communication with your partner in this situation? Your post details your line of thinking, but it doesn't seem to tell us what the discusson between you and your partne was. In a case like that, I may even send both teams to the bench quickly (because you have sporsmanship issues) so you and your partner could discuss what was going to happen without having to worry about the ugliness escalating. As far as getting it right, who know? Definitely a had to be there. It sounds as though neither you or your partner had a clear idea of what you had on the play when you hit your whistle, which is always a contributing symptom to a goatf#@k.
As far as the coach, you should have stuck him early. He was teeing off on you from the get go in subtle ways. The varsity guy was right. I had the good fortune to have worked quite a bit of smaller school varsity before I worked the larger schools in my area. I was not about to take crap from a lower level coach. My first time through the league, I think I was having to call 2 T's a week. After that, the coaches figured out that I had a decent grasp of my job and I wasn't going to be worked. They seemed glad to see me on their games and I still have good conversations when I show up for varsity games and I run into them. They'll respect you more if you take care of business.
Lastly, your partner told you not to T the coach only because the varsiy guy said you should. What level does your partner work? My point is, yeah, you can't go headhunting because of what an official that isn't on the game thinks you need to ding the coach, but the official in question has an understanding of what is acceptable in your area and he thought the coach was over the line. I'd have taken his advice and, not making one up, but finding one to call. At some point you will be hoping to work with the varsity guys and they are going to want partners who take care of business when you have to.