The swingarm will bolt right on, what that leaves you is a mount for any modern yamaha sport atv rear hydro brake caliper,
you can use the 88-02 axle w/ floating disc for hydro brakes, and not need the 03-06 axle with it's stationary disc
you will need to fabricate/weld ....
a mount on the frame for the master cylinder, welded or bolt on
an extension onto your existing cable pedal to connect to and actuate the master
or swap over to 03-06 footpegs/brake pedal for the hydro system, then mount the master to match up to that pedal extension.
If your fab skills feel froggy and you decide to proceed, we'll get into it further