I said this in the goat thread, but the possible plays that the Pats could run at 4th-and-3 were quite limited. No chance of a running play. Highly unlikely that they go downfield at all. Basically, the Tampa D is playing for a pass in a 5 yard window around the sticks. Pats were 2-9 on 3rd down during the game; the chances of a conversion there are definitely lower than the stat sheets.
As for the practice kicks: the main purpose of the warmups is to get a feel for how the kicker's leg looks. The coaches have the best info in terms of any nagging (and unreported) injuries their kicker may be dealing with. In Folk's case, it was known he was dealing with an issue with his plant leg. But if he is booming them in warmups, it's safe to conclude that the injury was less of an issue than feared, and that he could be counted on to at least make an honest attempt at a long kick. Given that it missed by inches, I fail to see how it would be the "best outcome"; a made try was well within the error bars given the fact that it hit the upright. As, to be fair, was an outright miss.
Finally, can Brady drive the team downfield for a FG with 50 seconds left in a driving rain? Sure. Is it guaranteed? Definitely not.
I also would not have been upset if they went for it and failed. As noted elsewhere, the pass deflection at 3rd down was where the game was essentially decided.