I know a bit about these things!!
The draw knife is the principal weapon for shaping, and you don't need a travisher.........a simple bone will do, or animal horn. (It used to be called "boning"). Don't forget to do the edges.
I used to adjust team-mates bats using a plane.............Salim Malik would need a bat adjusting most weeks!! I used to shape the handle for him too, with a spokeshave. Re-gluing the string required a pair of wooden brackets with protruding nails to act as an unpowered lathe.
Phil Edmonds played against us once using a bat which was essentially just a handled stave..........unshaped, unfinished. It weighed about 3lbs, and once he got the swing organised it put the ball into orbit.......and yes, he won his bet!!
Who is selling you a handled stave? If I was doing what you are proposing, I would cut the handle in myself. I remember a story Duncan Fearnley told me about one of his bats that was returned after a few months because the handle was coming loose. When they examined it, it turned out that it had been dry fitted (ie no glue)!!! The guy had used it for week after week before the tight fit started to work loose........
Have fun.........I look forward to the photos!!
Mike