With Ho Chan swearing revenge on the turtles at the end of the episode, is there a chance he could be another main antagonist like the Shredder? He's actually been a fun villain and I'd love to see him come back.
That could also be the case, to him tech would just be another 'power', but I can't speculate on the likelihood on one or another.
If the Irma there was a human with powers like April (perhaps stronger or more mysterious) then she would've been an even greater target for abduction than April was.
Let's keep in mind: if Irma had actually been a Kraang all along then she would have had multiple opportunities to capture April, she could have done it quite easily, look how easily Subprime trounced the turtles, Splinter had trouble with him, April would've been a synch.
Instead of simply capturing April (possibly with Irma-drone at any moment, if that was indeed the case all along) in spite of that having been a major priority, they skipped that chance and instead used her only to track the turtle base.
But they would not have given that kind of leeway to human-Irma if she had powers stronger than April.
Donnie threw the dagger where he was sealed to the sea, which means that the Kraang in the Technodrome undersea might find him and give him a new physical body taking advantage of his powers to send him do the dirty work of dealing with the turtles and thus have his revenge.