Unhappy [Q] Rewarded for my stupidity

Greetings, I'm having a cascade failure and I'm not sure what to do next.

I signed with AT&T on Saturday, and took home a new S4 for free. About 30 minutes later it was rooted, and the upgrade from MF3 to MK2 was installing I removed some obvious bloatware, patched the mail client to bypass an Exchange server's mobile device management, and began to use TB to restore my apps.

I encountered some odd behavior with a couple of restored apps, and did a factory reset. Then, I decided that I wanted to get the patched mail client off the system, so I reflashed the MK2 update through ADB.

The reflash of MK2 failed because I'd removed chrome.apk . D'oh.

Then I thought I'd flash a stock firmware. I quickly found the MF3 tars in another topic. And because I'm stupid and didn't read the whole topic, my nice new phone is showing an ugly yellow triangle and says, "Firmware upgrade encountered an issue." D'oh, d'oh, d'oh.

I'm stopping before I waste any more time or do any more damage (not that I think I can eff things up any more).

Can I fix this at home?

Or should I just take it to the Samsung Experience Shop at the nearby Best Buy store? Will they believe me if I tell them that the MK2 upgrade trashed my phone? The loader says, "Samsung Official," but, also, "custom." Both Knox lines read 0x0. Does any of that matter if they're reflashing as a courtesy?

If they flash MK2, can I get root ..... I'm guessing, no, but probably someone else knows for sure.