The Galaxy S4 Active is barely 4 months old and shipped with Android 4.2.2 aka Jellybean - if yours has Gingerbread on it (Android 2.3) something is very wrong.
And GS4A's are not sold unlocked, even from AT&T. You have to buy one that's carrier locked, then contact their support to get the unlock code (as I understand it). Even paying full price for the phone off-contract in an AT&T corporate store means you still end up having to contact their support by phone, providing the necessary info, and they'll provide the unlock code as required - the store personnel just don't do that or even have access to those codes even if you pay full price on the spot for one "unlocked."
As for moving the apps to the microSD card, I don't think that's a possibility with the stock apps; your best bet to get rid of them is with Titanium Backup (the paid version) and freeze 'em all out. I could be wrong on that so someone else can answer it perhaps.
The LTE capability of the GS4A won't work with Verizon's CMDA network that I'm aware of, and obviously Verizon isn't a GSM carrier at all so there goes that idea too.
Are you 100% confident of what you actually bought?
Currently in between devices...