Iride01 

1. Do you really have a 10 speed freewheel? Though they are out there, I've never seen one in person. If you are certain it's not a free hub and cassette, then just look for a wheel set that has a hub for a thread on FW. But not knowing anything about your bike, most of us will be hard pressed to give you any info on what will be appropriate. If it is instead a free wheel and casstte, then look for a wheelset in your price range that comes with a 10 speed free hub. If you can't tell from the advertisement details, then call or email the vendor with that question.

edit... Oh ten speed bike, so its really a five speed rear. Stop that. Ever since the turn of the Century, we started referring to speeds of a bike as only the number of sprockets on the rear. You ought to be able to find a inexpensive wheelset with a thread on hub for your freewheel. Might just get a new freewheel too. FW's are cheap.

Regardless, the OLD spacing on the track hub probably isn't the same as your bike. And again, you'd likely need to have the wheel dished to properly fit your bike. So why not just get a wheel that is made for your type of bike.

2. A 185 pounds, I wouldn't be concerned with needing a special wheel or spoke count. Your weight isn't enough to be a big factor for your average run of the mill wheel sets. Unless perhaps you have pegs on the rear and like to do wheelies and bounce up and down on the rear wheel.

3. High flange or low flange is fine for what your normal bike riding is. The use of the high flange helps build some strength for the extreme forces the powerful track cyclist put into their wheels while competing with each other. It generally makes for a more uncomfortable ride. But maybe only marginally. I doubt you'll be putting your bike to the extremes that track cyclists or any pro cyclists do.