A lot of codes, many of which could be from 1 cause.
A disconnected hose......the right hose, could cause those codes.
But, so could a lot of other things.
Your 2003 is a lot newer than the 1996 that I have experience with, so my pictures might help you SOME, but there are a lot of differences.
You ARE correct, lack of vaccum to the directional doors should have all the air go to the defroster......no defrost in Wisconsin right now is NOT a good thing.
Hopefully, you can find posts from folks with 2003 Windstar that can give you some pointers.
Also, hoping that someone with a 2003 will chime in.
If you are looking into doing the isolator bolt replacement.
You may already have found this link, but I repost it here because it is just that good for what you are doing.
http://leckemby.net/windstar/windstar01.html
Note that the 2003 should have the improved front valve cover in place already.
Also note that the 3.8L Windstars that are older than 1999 have the PCV valve in the rear valve cover and the breather tube in the front valve cover.....so looking at my pictures will cause you confusion in that regard.
1999 and newer have the PCV valve in the front valve cover as shown in the leckemby link.
While working around that intake....don't forget to verify that the IMRC shafts are connected to the electrical IMRC actuator.
It is common for the clips that connect the 2 shafts....1 shaft for the front bank butterfly valves and the 2nd shaft for the rear bank butterfly valves.
You can purchase replacement clips.
If you don't have clips handy at the time, fasten the shafts so that the butterflies (flaps in the 2nd port for each cylinder) are CLOSED.
Your engine will run just fine with them closed all the time, you just don't get that power boost when you accelerate hard.
If they are open at lower idle speeds, you can have some of those codes that you are getting.
I'm sure that you can see where 1 bank being open and the other bank being closed will cause the computer (PCM) to go crazy trying to control an unbalanced airflow entering the cylinders.
Don't hesitate to post back if you have any questions.