First off, what do we define par as? I generally say that on an open or slightly wooded course (like Blue Valley), par is the number of drives it takes to get inside 100' + 2 to get up and down.
The par 4's on the "Little" Blue Valley configuration are #6, #10, and #18. Course designer Jack Lowe and I had a long conversation about #18 (#16 in the Big Blue Valley configuration); when the tree to the right of the tee finally dies you're going to watch pros through big hyzers to the green. At that point, we may have to re-evaluate the par (or move the basket). For now though, it's a par 4.
#1 is 520' downhill. I saw some advanced players put it within 50' warming up.
#4 on the standard course is for sure a par 4. On the short course, it's a 350' tunnel shot or anhyzer flex over the top. Easy to get within 100' off the tee.
#6 is a par 4.
#7 is one of the tweeners on the course It's tough to mark as par 4 though since it's so downhill. But this is one of the bigger points on convention.
#10 is a par 4.
#16 is a pro par 3. It takes a big anhyzer to get to the basket (Jordan in advanced put it 12' from the bucket). Generally though, an anhyzer that's decent and in bounds will leave you 100'-150' short onto a green that isn't too tricky.
#18 is a par 4.