Solved! I think the problem was twofold: the version of Classic I was using required a ton of resets before the balance got back to normal, but I also was likely not leaving enough buffer for the transaction fee when trying to transfer the funds. I installed HD and was able to spend into the new wallet. thanks for the help

Thank you, but "Repair wallet" isn't one of the options in the tools menu. I installed it in late 2013 and don't think it's ever been upgraded. I just tried installing Multibit HD but apparently that uses different security, so I can't open my existing wallet using it. Is there an early build I should install?

Also, I just tried looking up both the sending and receiving addresses on blockchain.info, and neither have a record of the transaction so I guess that makes me feel slightly better. Must be a MultiBit glitch, right? ....right?

I tried making a transfer to my Coinbase wallet yesterday but it never showed up and the Multibit balance reflects that it's gone. The transaction initially appeared as unconfirmed / seen by 1 peer, but it stayed that way all day. I started to do some research and found another post on this forum from someone experiencing a similar problem. The suggestion made to him was to reset the blockchain. So I tried that but after doing so the transaction doesn't even appear in my history and the balance is still reflecting the transfer was made. I have tried reseting the blockchain 3 times at this point and still no luck. It's like Multibit just erased that BTC from my wallet without a trace. This is giving me some pretty intense anxiety. Do you know what is going on? Any help would be very much appreciated! 

PS: I took a screen grab of the transaction info but I'm not sure what to do with it.