Pinebook Pro as an all-in-one boat server?

[nhm]

Hi Folks,

I would like to make an  all-in-one plex media server and wireless router for a boat.  Here's what I'm looking at as high priority items:

1) low power usage, run off 12v batteries
2) low physical space usage
3) no HDDs (waves, power!)
4) Host local wifi network for boat
5) preferred list of remote access points to route through (Home marina, other marinas, phone hotspot, etc)

I was first considering simply using a RockPro64, but it looks like I would need to make a custom case for it or use the NAS case which is larger than I'd like.    I'm considering instead using a pinebook pro, leaving the lid closed, and mounting it inside a closet.  A couple of bonus advantages: 

1) Battery backup
2) integrated screen/keyboard if network goes down
3) Functional as kids laptop if project doesn't work out.

Downsides:

1) m.2 tops out at 2TB while SATA and U.2 offer larger sizes (and can be cheaper/GB)
2) Don't strictly need the keyboard/trackpad/screen (but nice to have).
3) Heat a concern inside a small closet?

Any thoughts on whether or not this would be a good plan?  Any concerns with power/heat or ability to host a second wifi network (USB3 dongle?

Thanks!