Most attics are vented to ambient, and those that aren't typically have insulated roof decks. Either way, the house should not be heating the shingles. On top of that, the photos I've seen show them on furring strips so there is an air/ ventilation gap under them.
They are dark which will help if any part is exposed. Sone other systems have built in heaters for snow removal.
As to snow stops, those come in self adhesive version that could be applied to inactive shingles, but yeah they would need to plan for a row of those.