1. Hobie Dealer, Murrays. Salty Dog, etc. Technically called a Mast Bearing.
2. On my 14-Turbo, I have to raise the mast with the shrouds loose (pinned in top hole), then remove the step hinge (while things are still loose), then tighten shrouds. I tighten shrouds by pulling down/out on the trapeze wire while helper moves clevis pin to lower hole. I suppse you could uses the main halyard if you don't have trap wires. However, if your on a stock 14, I think they are supposed to be run with a loose rig:http://www.hobiecat.com/articles/hobie- ... -guide,86/http://www.hobieclass.com/site/hobie/ih ... 0Guide.pdf
3. Yes, take the bolt out (before tightening rig too much as described above) so the mast can rotate while sailing. I completely remove the hinge so that it doesn't accidentally get caught by the mast and get bent. This is a common occurence, and the hinge doesn't work properly after it's bent up.
4. That's the lower block of a vang, correct? I don't think anyone really uses those, but you can get SS screws with square nuts that fit in the luff track. With these, an eyestrap could be attached. (You should have a downhaul cleat attached this way.) For sure, you don't want the vang attached there. It will impeded mast rotation and lead to a bent up hinge as described above.