Hi and welcome... I've done most of the items you are asking about. If you are mechanically inclined and can follow steps, this should be a piece of cake.
#1. Easy enough to do, since you need intake gaskets...do it at the same time and they will be much more accessible. Time: See #2
#2. The alternator, supercharger, throttle body all come off easy and this is a fairly easy thing to do. Merely a matter of time. On the supercharger, I would suggest changing the oil and the coupler. Time: 8-10 hours if you haven't done it before.
#3. The blender is technically called an "Air Mix Actuator", Bill B meant to say they are about $40 from www.gmpartsdirect.com
. Time: ~2 hours.
#4. If the compass is also intermittant, we probably need to look at grounds. In the Techinfo section there are instructions for taking a cluster apart and they are the same for your year. I would take it apart and look for loose connections. The mileage is stored in that information center part of the cluster.
#5. You can get a press on pulley, although if you plan on changing to smaller/different sizes later a Multi Pulley System or MPS is suggested. The other work would need to happen first along with other checks to make sure the engine is ready for this mod.
#6. Unsure about the Thrasher kit. I know the kit Intense-Racing sells is tested and proven here on the forum.
As you are ready to tackle the projects, post it up and we can help you source the best parts for the best prices, tell you the tricks and tips on how to do things. Personally...it takes me about an hour to swap a supercharger, once I learned the tricks.