I believe that year's Envy Prodigy came with an IHC fork, so you couldn't use it with SCS. You would need a standard threadless fork, not an ICS or IHC fork, in order to use SCS.

You couldn't actually tie-dye grip tape because it's not flexible enough and it would ruin the adhesive. However, you might be able to use some kind of paint pens to decorate it similar to tie dye.

HIC requires oversized bars, so any oversized clamp would work.

It's sorta-possible. Some bar builders have done what they call "tapering" bars. This is the process by which a larger, oversized bar (pipe) is welded over the standard diameter bars that have been cut shorter. Essentially, it makes the bars look like this terrible diagram:

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|  |
|  |
|  |                              |--------------------|
|  |--------------------------------------             |
|  |--------------------------------------             |
|  |                              |--------------------|
|  |
|  |
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However, that's not a very practical solution since it requires welding. The short answer is no, you can't up-convert standard diameter bars to oversized bars.

Those should work as long as you get the oversized version of the clamp to accomodate for the aluminum bars' oversized outer diameter.

It's a learning process. You can learn what types of parts will work together. You can also try our Scooter Configurator. Your best option is to speak to a retailer who will know all the parts they carry and the compability. Inward Scooters is great about helping people figure out what will work together so you can order the right combination of parts from them.