I think you will find your mini will bloom well into the hard frost season.
Our local rose society used to host an all mini rose show here in the Southern Tier the first weekend in October and had about 350 minis entered in the show and the quality was wonderful.
Meg

Minis bloom all season just like bigger roses. I can't speak for that particular variety's disease resistence, but in general, my minis seem more disease resistent than their larger counterparts in my climate, but as susceptable or more so to spider mites (close to the ground, harder to get under with a water wand if planted in the ground).

Although they were originally bred and are still sold to be disposable (ref the 3.99 potted minis you find in supermarkets and box stores with no variety name), if kept watered, repotted or planted in the ground, they will grow quickly.

I'm fairly certain the two biggest mistakes made with these little darlings are trying to grow them inside and leaving them in their original pot. The latter being a mistake because they are already well root bound and its nearly impossible to keep the soil moist enough to keep the rose alive.

Suz

You do need to deadhead, meaning to remove the old blooms once they are finished. You can either clip them off or snap them off.