Shocks normally are fairly easy to compress ... some force is required usually though as they are all gas-filled these days. Springs are a different matter.
There are no special tools needed for front suspension work on a Windstar ... if you are not going to compress the springs. But I would recommend jacking up both sides fully (wheels off ground) at the same time .... if you try to work on one side at a time the anti-sway bar is going to be working against you.
The sub frame is held in place by 4 bolts. I recommend you first remove one of the rear bolts totally just to see how long it is and all. Yes, lower the rear of the sub frame a bit to get better access to the anti-sway bar bushings. Work safely!!