Yes, you can credit WP flights to UA.
No, they don't count for status.
In the past they have been 500 miles per segment.
I don't know how UA is going to count them now with the devaluation of its own mileage earning on <500 mile segments to actual flown miles.
I've found that I even can get UA miles on IslandAir award tickets "bought" with UA miles; just put your UA number in at IslandAir OLCI