Hmmm...depends on how much of the work you intend to do yourself. For basic dissasembly/re assembly, and over and above the normal sockets, spanners etc... minimum I would suggest you may need.
1. A Flywheell puller*..threads into the end of the flywheel allows you to pull it off it's tapered shaft
2. A Crankcase puller/pusher* combined...for splitting the cases, and later pulling them back together.
3. Torque wrench* approx 15 - 90nM range
4. Feeler gaugues for checking ring gaps and the like
5. Clutch basket holding tool***, to hold the basket when you undo the clutch hub nut(tight!)
Getting more complex now...
If you are going to do any serious measuring then a bore micrometer, dial gauges, v blocks &Co. for checking crank wear etc...a ball hone for the cylinder walls deglazing.
When rebuilding,
a compression tester would be useful, to check the 'healthy' reading for future reference.
Piston ring compressor?...I don't use one but some do.
Heat gun to expand crank cases before putting chilled bearings into them(they are an interference fit).
Rawhide mallet..for any 'gentle' persuasion (a.k.a. Birmingham screwdriver :-)
Copper slip grease, waterfroof grease, 2 stroke oil(to lube cylider walls etc..)
I would suggest you can borrow/hire many of the above tools if you know a friendly machine shop. Those with an * are really a must, if you don't have them you risk doing damage at that stage of the work.
I'm sure there will be many other comments on this, but the above I would regard as comprehensive enough for a first time build.