Re: remove drive shaft
You would likely find an OEM shop manual useful at this point.
Why don't you look at the parts list for your motor on BRP Evinrude website.
See attached
Typically, you will need to disassemble the gearcase, since the driveshaft has the pinion fastened with a hex nut reachable only from within the gearcase. I would get the book to see exactly what you need to do.