I haven't done the entire Laurel Highlands trail, but have done 3 sections of it.
All the shelter areas I have seen are along side creeks - water shouldn't be an issue. Also, where I have seen warnings on the water wells about contamination, the pumps still work - you could always use the well, but treat the water you get from it. The wells take a lot of pumping and effort to use - it is easier to just treat water from the stream, even if the well was not contaminated.
You may not see a lot of water between some shelter areas, however.
There is little bear activity in that area. There may be a few, but I have never seen a sign of one, or heard of anyone seeing one. Even if you did manage to find a bear, it wouldn't be a crafty bear stealing properly hung food bags like in Yosemite or the Adirondacks. Just hang your food in a tree.
There are typically 6 shelters and an abundance of tent sites at each shelter area. You need to reserve and pay for both shelters and tent sites. It can be done on PA's state park website (I think tent sites are cheaper). There is split firewood available for use, free, at each shelter area. The fireplaces in the shelters keep the shelter quite warm. I imagine you will have most shelter areas to yourself this time of year, especially during the week.
You can tent camp only in designated shelter areas (not in other areas along the trail). However, the shelter areas are large. Its easy to find a tent site 50 yards or more from the shelters, bathroom, wood pile, etc. if you want some solitude from the few people you see all week.