Looks wonderful. I hope it works for you! 
Depends. It would struggle with deep penetration due to resistance, which is why two Handys in sync is used for that purpose.
It’ll work pretty well if you’re alright with shallow penetration, such as demonstrated in this old reddit post:
https://www.reddit.com/r/theHandy/comments/rfkhvn/who_says_handys_are_just_for_men/
(Depending on your anatomy it might handle deep penetration better, especially if you go with a smaller dildo. Do mind the friction at high speeds.)
Thank you! I had the same idea, but I still wanted to give it a shot. It could be too much resistance for Anal too.
I was interested in seeing if I could make this work with what I had on hand.
I’d definitely be extra doubtful about anal. Might work, but would probably require compromising with the dildo size.
maybe I should start by removing the fleshlight inside the case so there is less weight ! 
Looks like you have access to a 3d printer or service.
Agree with everyone on the resistance comments. Check out the OSSM. I found it did not disappoint in this way.
I tried my setup during my lunch break and it was an absolute failure the handy is not strong enough. But everything stayed in place. I will check the OSSM thing later when I have more time It looks a bit complicated.
So it’s DIY but Research and Desire will sell you a kit that is ready to assemble, to save you from having to source the right parts and 3D print a bunch of stuff. They also have different packages if you would like to 3D print but want just the non-printed parts and pre-programmed controller board, etc.