Cloaking device was on lone from the romulans , no other federation starship was going to be equipped with it. Ablative armor isn't easy for refitting you would have to tear the entire skin off a starship . And quantum torpedoes were tested on the defiant yes but the Enterpirse-D didn't last that long after that.
The Enterprise-E had Ablative armor and quantum torpedos.
yes, but that was in violation of the treaty of Algeron (spelling?) in wich the Federation agreed not to develop or use cloaking technology. Not that this was the only time the treaty was violated, such as the Holo-ship in Insurrection and those Cloaking camoflage suits probally would have been a violation too.