The Redundancy complex form (Data Trails, p.58) can only target a device. It can't target a technomancer (not a device), but even if it could, it wouldn't add boxes to a damage track they don't have.
CRB p. 252
"Each complex form entry has a
Target describing what it works on. A complex form with a Device target can also be used to target a persona."
emphasis from book itself.Technically, yes it could target a technomancer, and really quoting this because I hear that first part of statement a lot (Says device, therefor can't target persona, on a lot of Complex Forms). That deals with the target type portion. But...
As to the second part (adding boxes...) I would say that it adds "psuedo" boxes only for the purpose of matrix damage, not normal stun damage from a flash bang... But that falls into the realm of interpretation of "don't have a
separate Matrix Condition Monitor" (quote from CRB 251) vs simply saying does not have one at all... So depending on your reading, they don't have one at all, or don't have a separate one (as in combined Stun/Matrix)... Personally I am not gonna quibble over a few extra boxes for the techno, otherwise your pushing them even harder into the realm of just using a cyberdeck, put a machine sprite in it, and then run an agent on top of it, and then run redundancy on the deck, you come out way ahead (even more so if you use the Kitbashed deck from KC). But that is opinion.
As for the Cyberadept, overdrive damages a device, and it depends on how you apply the extra boxes. Are they the first boxes of damage, or do they add to the end (meaning that you could have enough damage that would brick it as soon as you drop it, or was it ablative damage first. I always apply it to the end to prevent this kind of abuse, just like you would for spell increased body). Also you are now maintaining 2 complex forms for up to -4 penalty depending on drugs (if your GM allows psyche to work), focused concentration...