The frequency of blooming depends partly on the canna variety. Some bloom almost continuously and some intermittently. It also depends on environmental conditions such as sun, warmth, water, and soil fertility. Cannas like all those things in large doses. Since yours are growing so well, I'd say it's a characteristic of the variety, which would not be very impressive to have bloomed only once during the whole season.

The purple or reddish shoots are normal in some varieties of canna and in certain varieties of other plants also - roses, for example.

What's pushing up out of the ground? The rhizomes? Maybe the rhizomes are just pushing up soil as they expand. A raised mound can form around the base of vigorously growing canna.

yes, it's the rhizomes that are pushing up out of the ground. I went ahead and split them up and planted them deeper, further apart. They seem to be doing good.

I do find it strange that they are doing so well yet have only bloomed once, and unfortunately i realized after I cut the dead bloom off that it was a seed bearing bloom.

This is only my first year really growing cannas so i will do my best and hope they doo good because they are beautiful.