USAA accepted my Elio stock. It took about 20 minutes on the phone with them and the guy helping me said they've done a lot of "L-EEE-OH" stock transfers. I started by using USAA's chat function but basically, that wasted time as they had me call 1-800-531-8747 option 2. They asked a bunch of questions of which the answers were easy. Mostly, it was either my total number of shares, zero, yes, or no. Simple. They then put two documents on my USAA web page that I had to print, sign, scan back in. He said because of the number of transfers that VStock is dealing with, it is taking about 2 weeks for the transfer to go through.
So, I'll report back here --- edit this post, I mean, with how long it took for my Elio shares to hit my USAA account. (No fees at this time to report)