The manual recommends storing between 30 and 60% battery charge, and charging every 30 days. Is there someone who can car-sit for you and swing by once a month to check on it?
Forgive my naiveté - is this something a dealership can do? Although that would mean sitting outside, at least they can keep an eye on it?
Sitting for that long on the tires may cause flat spots. This can be reduced by over inflating them a bit and then reducing them upon return. The flat spots will round out after the car is driven a bit allowing them to warm up, flex, and return to normal roundness.
It can be avoided if you can support it off the tires for the duration.
The car should be able to retain some charge for the duration. I'll assume you'll be able to plug in a home charger when you return. Do that and charge it for a bit upon return.
You might consider taking the panel out of the frunk area and connecting a trickle charger/battery maintainer to the larger 12V battery.