After rereading your post here are some more thoughts:

How many tools do you plan on buying to remove cassettes? If you have a shimano equiped bike you only need the one for that, and the same for if you own a campy equiped bike...if you desire both for versatility in case you are working on someone else bike that is setup different from yours then you can buy both for less than $20...thats not very much for a couple of tools that will last well past your lifetime. The only other thing you will need is a chain whip....this can be fabricated very inexpensively with a spare piece of chain, flat metal bar, and a drill... no need to spend big bucks on a commercial chain whip. But a park chain whip can be had for $15 online and should last your lifetime as well...I have a chain whip that I still use that was purchased in 1988.

You don't need a full set of cone wrenches. Figure out what size cones you have on your hubs and buy the two that you need...most likely 13 (front) and 15mm (rear). It is nice to have two of each size but totally unnecessary.

For removing cranks, you can buy a square taper crank arm remover for less than $10 and the newer ones for $15 or less. Again these tools should last the home mechanic their lifetime.

The chain cleaner device you mention is nice but unnecessary, there are alternate ways to clean the drive train that are as or more effective and use less degreaser.

There are surprisingly few specialized tools (bike specific) that a home mechanic needs to completely build up, tear down, or maintain a bike.

-j