Optima batteries suck.. Don't buy them. They are over priced and made for a different application.
The nuc may be taking in DC. If this is the case you want to get something that can put 19vdc to the unit at 65 watts. You don't need an inverter and all the extra headaches those can provide.
Get whatever battery is suggested for your truck and leave it at that. You can always add a UPS type battery to your build for the computer if you want but you probably won't need it.
Also as far as monitors go. You don't HAVE to have a touch screen. If you are already looking at getting a keyboard/touchpad you don't need a touch screen. You could get a Leap Motion that will let you do everything a touch screen would do and it is about the size of a bic lighter.