So the cyl units are permanent?

They'll probably be temporary units available for a limited time as they were in the summer, bridal, spring banners. Would be lit if they were permanent addition, but I don't think that will be the case. I wonder what the fall and winter banners will be like if they decide on more special edition heroes.

The future is full of surprises I suppose.

I don't believe they are, as the new announcement says they end on the 15th. This could just mean the banner, but I think they will disappear then.
Plus, it couldn't hurt IS to have the brave heroes make their triumphant return sometime in the future for even more money.

still believing in brave heroes for sacred coins. would fit character and I think it's too early for powercreep. would also increase areana assault participation and variety

Very likely. There's a lot going for these units being permanent. They were never announced as special units, even their banner notice just released says "New heroes" not "Special heroes" and there isn't a notice saying that they may or may not appear in the future. It also has the new heroes format. Notice all special banners have a white background, all new hero banners have a black one. It's very reasonable to assume these are permanent units. And if it was limited edition, intelligent systems would have surely pointed it out every 20 seconds to make sure we spent all our money.