Thanks for the replies.
We went down to the Riverwalk and the Alamo for the first half of the day (it was as expected...but the wife was happy) and made it to Fiesta Texas at opening.
For Fiesta Texas, we ended up buying the 4 person season pass deal, which included free parking for 2016 for 50 dollars more than it was just to buy four tickets for the one night holiday in the park. I am not bragging that this is a good deal.
The value for the experience was overall good for our family. We have an infant and a 3 year old who can't ride anything, and a 6 year old with limited ride selection. Being early was great because the wife and I could both hit the rides with the 6 year old while hanging out with the 3 y.o and infant. The Kidzapolis area was really pretty good for the 5 and under group. My daughter could handle all rides, but they have a pretty restricted height limit. Our 6 y.o. became addicted to Pandemonium and Road Runner Express. He was tempted to ride Iron Rattler, but I think it was all bluff (and conveniently for him was closed).
The park itself was well done, particularly the first entry area before branching out into the park sections. Santa's Castle was lightly attended, and it might have been the real Santa Claus. Recommend skipping if over a 30 minute wait but a must see otherwise. We saw the Magic of Christmas show which was very well done. I didn't realize it was an approx. 500 seat auditorium. Get there about 15 minutes early and expect everyone else to be late. The train was well done as well. Bottomless Hot chocolate for 8 dollars was good.
Overall:
Pros: Light crowds at the beginning (4 pm-7 Pm) allowing for quick ride access, and good rides for the kids. Clean park. Friendly Staff. Holiday Cheer. Nice Lights. Good shows. Fair deal if you get the season pass option and might come back again. Value improves with kids age.
Cons: Crowded late. Ride availability was sporadic (rides were opened and closed intermittently), Not much intermediate ride availability (if skiing 25% bunny/green, 25% blue, 25% black, 25% double black). Expensive if you don't have ride riders/limited time/never coming back.
Summary: 6.5/10. Recommend.