Lifepo4 is pretty much the one type you can safely leave unattended, it’s very very hard to get them to burn and even when they do it’s mostly smoke. Lithium is the big flame/boom one. The trade off is less energy density compared with lithium but for home storage thats less of an issue. The batteries i shared even feature fire suppression systems (basically an automatically deployed fire ratardant foam internally) for additional protection.

Building a little box of insulation around the batteries using some foam board panels and a water heater blanket with some water pipe heating tape you can get at most hardware stores would be the cheap easy way and should help with the colder month temps. And is easily picked uo and set aside in warmer weather