OP, I'm so glad that you won the eBay case. Now I hope you can win the chargeback case, if he files. Also, I was skimming, so I don't know if you already said... Did you get the item back from FedEx already? I would hate for him to still have the ability to pick it up at FedEx or have them deliver it.
Hi all,
Yes, unfortunately the package did ultimately bounce back to me.
He opened another case on eBay (this time it was an item not received case) and made more threats with chargebacks.
Same thing, offered a partial refund etc. He gave snarky responses instead of coming up with a resolution, etcetc. So when his chargeback finally began officially, I ended up having 2 ongoing cases. had to call into eBay myself to get one of them closed. I thought this would be automatic on eBay and Paypal's behalf but I guess not!
Long story short, he won.

So he got his full refund and I was slapped with a $20 chargeback fee from paypal + $101.50 final value fees from eBay.
Paypal ultimately refunded me the $20.00 chargeback fee, but I had to ask for it. They didn't give me a lot of trouble for it at all. I just stated my case again in 1 email and they offered the refund immediately.
eBay also refunded the $101.50 final value fees, but I had to ask for that back too! This part actually took a while because they had to transfer me to so many different departments and supervisors since it was a high value case. They did not give me trouble about it either. They were very pleasant, it just took them half an hour on the phone because each rep kept transferring me. I was surprised this wasn't automatic!!!

If this ever happens to you, make sure you call in and ask for your fees back!!! I almost forgot about it because I have sold so many items over these past 3 months and I set up automatic payments for my eBay fees!
The buyer actually also sent me another nasty message after he won his chargeback!
He had been blocked but he's still able to message me! Ugh. I messaged back telling him to never message me again and he has not done it since. Hopefully it is finally over now.
Anyway, bottom line: I was able to win the eBay case but unsuccessful with negotiating partial refunds in the chargeback case. Also,
eBay was going to keep my $101.50 final value fees and Paypal was going to charge me that additional $20 if I didn't speak up! :/ Make sure you fight for yourself if you find yourself in such a situation!
Email them! Call them!
I don't know if any of this was worth it but I ended up with no monetary losses... although I did waste a TON of time and it was a huge headache.
It could be worse! At least I got my item back!