Arrested for alleged shoplifting in Tennessee Walmart self-checkout with friend

so last Friday, I picked my friend up from work. she gave me $20 for doing so, and asked me to take her to Walmart nearby, to cash her check, load a card, and pick up some Valentine's, household, and grocery items, as she was going to cook because I'd picked her up and it was Friday night. I obliged. (lots of information included below to try to paint a picture since Walmart will have video)

we have a sort of hybrid big brother/little sister + gay best friend/fag hag relationship, so we were pretty much keekeeing through the store and I'd occasionally help her with difficult items with dog food. so naturally we took too long and when we got ready to wrap up, it had been about two hours and it was getting late and cold. I had pretty much been tagging along, but I'd picked up four SNAP-eligible items, and when we were in the self-checkout line, I ran to get another. by the time I returned with it, she was already at a self-checkout, and so I joined her. first, I separated my four items out and then proceeded to help her with her items, basically organizing the cart, pushing her bagged items to the back of the cart and her unscanned items to the front of it nearer her. I even asked her if she'd scanned a couple items. (I did notice she was moving pretty fast, but we were in a rush, and I met her working at Family Dollar; fast scanning is second nature to us.)

after she'd done, I quickly scanned my four items, paid, and followed her.

no sooner had we exited the self-checkout corral did the gates open and a lady came asking to see our receipts. we quickly obliged, gave them to her. she asked us to come with her, we asked why, she said some items didn't scan, we said what items, we'll pay for them. she said we'd discuss that.

get to the back room and never actually discuss that, though we're asking what wasn't paid for the whole time. in particular, I'm asking, because I only had four items, and I was already behind schedule and impatient. another LP lady asks for our IDs and we present them. while she's looking us up, I pull out my phone to call my mom, who's a police colonel in the city. I'm told I can't use my phone as I'm being detained. I didn't understand how Walmart could detain me without law enforcement, they said they had a "County Officer" present and did I want him to come in, I said yes, and when he got there, I asked if he was on duty or if he was acting on behalf of Walmart, which no one would answer. ...that went over well, I think.

right after that, LP lady finds where I stole a DVD from Walmart in 2008 when I was 18 at college. now, I admitted to it, the guys were pretty cool, the police weren't called, and I really don't remember being banned from the store let alone all Walmart stores. but the stage is set.

when the police arrive (with a "Fuck y'all in here stealing?"), my friend changes tune from not knowing what was scanned to maybe she didn't scan the dog food and some other things, which the officer took as an admission of guilt. I still didn't know what of my items was allegedly stolen, and the police officer thought I was lying.

it turned out I hadn't scanned a $10 jar of coconut oil.

the value of the unscanned items was $182.

they charged both of us with Theft of Property involving merchandise under $1000, but I was the only one transported, as I had a "history of theft" (the one incident 13 years prior), and she didn't (she actually has the same charge from a year ago, still pending). I'm pretty certain it was less for that reason and more for me questioning Walmart's LP team and the police when they arrived.

regardless, this charge is bogus, and it's precluding me from getting a job and moving OUT of Tennessee. what should I do to beat it, and quick? I don't have money for a lawyer-lawyer, I'm black and in the South, and they've already moved the arraignment to May 3rd from February 15 due to the snowstorm. I actually called Walmart customer service about it, mainly the fact that I felt singled-out by the arrest, and the rep was outraged herself and transferred me to their ethics department, who was not pleased either. maybe they'll intercede?

TL;DR: got "caught" "shoplifting" in Walmart with my friend, but it seems she was doing the shoplifting, and I just forgot to scan one item. two separate transactions, one huge, one small. same charge, friend doesn't get transported, I do. best strategy?