The Schwinns have a little more spring action & a softer ride (but they can feel a little wobbly)
The Monark is more solid feeling but has much less spring action. (but they look AWESOME!)
If you can get a decent quality suspension fork it will be a far
better ride than the other 2 choices which are mainly used for
the look factor.
Does your frame use a 1" or 1 1/8" steering tube?
The choices for a good suspension fork are more limited in the 1" size.
Also what kind of front brake do you plan to use? Disc? Drum? or V brakes?
I agree with what MOtorbicycleraging said--a modern telescoping-style MTB fork will ride the best, if you get one that has oil-dampening, which the cheaper ones don't have.
Last time I looked you could get a previous-year Rock Shox w/oil for around $150 or so.
None of the vintage-style forks really ride well or are very stiff/strong, they are only just for looks and riding at casual speeds.