Yes they will be fine eating only pellets for a week, but if you go with an autofeeder before you leave you need to make sure it is working properly and not dumping in a ton of food. My fish will go days without eating anything other than NLS pellets from my autofeeder just because I get busy and don't get around to feeding them.Will they be OK eating dry food for a week? It's New Life Spectrum.
(I usually mix up their feeding, going from frozen to dry every other day)
Honestly with the fish you have, assuming they are healthy, they should be able to go a week without food without any issue. IMO your ATO is the bigger issue if it can't go a week without being filled.