They waste is fairly solid unless they have parasites. They can get the runs from time to time however for the most part it reminds me of a tiny dogs waste.
Yes you can freeze their food. I make a months batch at a time and add calcium powder when serving since freezing lowers the nutritional value a little.
You could do a 12in tall cage however i use 2ft tall cages because they need lights. Lizards in general have a light sensor on their heads "third eye" they source heat by looking for light, they also require UVB. That being said i stack my cagea as well. Having a 2ft tall cage allows me to wire my lighta inside and they are still far enough away to prevent burning from contact. I have looked into using RHPs for my blueys but to be honest they need the light source so the rhp would be used for ambients on top of the light and for themps i keep ny room at suplimental heat isnt necessary.
Baby blueys get fed frequently however i feed both my adults twice a week. Monday and Thursday. They can go without food for a week if necessary however if your pet sitter is willing to change the water i dont see why they wouldnt be able to put a small plate of food in the cage. They just cant leave it in overnight.
If you are seriously looking into blueys i suggest you check out bluetongueskinks.net this site has the most in depth care sheets the dos and donts of care and a complete list of foods safe and not safe for them. That all being said blueys have small clutches and dont always breed every year so most of the time breeders have a waiting list. You mentioned wanting to stay away from resellers HOWEVER LLL does breed some of their own blueys at their facility. Jen also breeds her blueys and they get sold through their store.
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