Hey, good questions.
1. Yes, that $372.37 is part of the total campaign's spend of $1,935.86
2. Phone call conversions only count if the call is 60 seconds long or done through a mobile phone for a click-to-call. Other conversions you're seeing simply indicate the phone number being displayed on the regular text ad in which the user clicks the ad and converts, in cases multiple times.
3. Same as the phone extensions, the social can be attributed to the association — OR — it can indicate someone +1'ing your company straight from the ad. Dig into the segmented extension data to break out what is what.
4. For dynamic, just make sure everything is logically set up and laid out. Dynamic campaign, dynamic extensions, dynamic ads. Just be ready for different data and possible skewing,