That was to be expected at such a cheap price. Obviously it was going to be a fixer upper. All those parts should be readily available.
If you need to replace the fill tube, I'd also launder the permanent bag and wash out the Emptor and disposable bag adapter. That way, you won't blow around someone else's detritus.
If the back wheels are toast, that will be a bit of a challenge as you need to take apart the Tech Drive. Not impossible, just not the easiest repair to make. Front wheels shouldn't be too hard.
The handle backing is super easy. All in all, you got your dream machine at the price you wanted. Not too shabby. The back wheels should be the only major challenge.