1) Yes this is the intention.
2) That would depend on the specific situation - any one of the suggestions you made could work. Wrestling an enemy down might mean a STR check (using the sliding difficulty depending on the size of the foe) whereas a weapon leg sweep might be roll-to-hit followed by a Dodge Save. Part of the system's design is giving you multiple points to use to adjudicate situations as you see fit.
3) Correct, although this was expanded on a little in the April update - make sure that's the file you're working from.
4) The chances are in the Magic book, updated very recently - make sure you're working from the most recent update.