Someone else may be able to talk more about pitching velocity and the all-Academic Game. I can speak to the experience of being there with two outfielders and just doing the tryouts.
The tryout is pretty consistent with showcase formats I've seen else where. Kids do each part of the tryout in alphabetical order by position. Kids run a 60 (on a very slow track; my guys couldn't break 7.0 there, but had run 6.7 in events before and after). They also do a defensive drill from whatever position they sign up for. OFers take a few balls in right with a 2 to 3 throws to third and 2-3 throws home. Velocity seems to matter more than accuracy. In think SS, 2nd, and 3rd basemen all worked from short.
Two rounds of hitting, 8-10 swings each round. If I remember correctly, All hitting on the same field. A lot of sitting around because everyone gets a chance to be seen by everybody.
I recognized a lot of scouts my guys had contacted before hand, and they did show up to watch the tryouts, so I can't say my kids weren't seen. And we saw them during the games that followed, too. I just think more contacts were made at HF or Showball than at Az.
Many people will say the tryout alone is worth the cost, and I think it can be. It just wasn't for us. A way to hedge your bet is to make sure your son is on a team as well. That will give him more opportunities to be seen. There are always teams looking for an extra player or two, especially pitchers.
One other thing to consider. My guess is that d3 recruiting is gonna be pushed later this year simply because so many early summer showcases may be postponed. That might make AZ more appealing since it's not til October and would seem to have a better chance of being held.