I live in the NE. And where I live, it's common for crawlspaces to be unheated and only insulated where a 'side' is part of a 'heated space'. So, in my case, I have 15' x 30' x 3' crawl, on slab, with the 'ceiling' being insulated up against our kitchen floor. It has 2 vents.
However, you may hear other opinions as to what you should do. As an aside, it may be prudent to find out what 'others', especially in your neighborhood (assuming there are similiar homes in similiar situations), have done to address your situation. Ask your neighbors, and talk to contractors. And if you go to Home Depot or Lowe's or some other Home Center, don't just ask the opinion of 1 person. Seek out the advice of a few people to be sure you don't get conflicting information. And DO ask questions, lots!
I think it's OK to put the 6 mil plastic down, along with some gravel or bricks along the perimeter. Do not put it on the joists. Yes, again, I think it's OK to insulate an wall or ceiling that's in contact with a 'heated space' (as I described above.) Be sure the Kraft is FACING the heated space. Don't compact it in between the joists. Let it 'luff' downwards and tack up chicken wire or run string around 1" roofing nails that you nail in 3/4" into the BOTTOM of the joists. In either case, if the insulation decides to 'fall', there's something in place (kinda like a spider web) to 'catch' it and hold it in its final resting place.
If you're getting standing water under the crawl where it's pooling in a significant way and NOT being reabsorbed into the ground, yes, I'd consider a sump pump. As long as the water can't / won't flood any 'livable space', you needn't get one w/a batter backup. When you 'size' your pit, make it a little bigger so you can put a 5 gallon bucket with a few holes cut into it (about 4" in diameter), and covered with some sort of 'screen' to filter any 'junk' that may flow into the pit. This way, your bucket only fills w/water and no junk clogs your pump.
If you need more info, start a new post. My best to ya and hope this helps.