Mixing slate stacked stone panel ledger and porcelain tile on shower wall - selecting thinset, grout and sealer?

I’m redoing my shower from scratch and fell in love with the combination of this Slate Multicolor Porcelain Tile and Splitface Slate Panel Ledger:

I have limited experience with tiling and have several concerns with this combination, for which hopefully someone could steer me in the right direction.

1. Is this even a good idea? Is this normal practice? Are there any potential issues (not mentioned below) I could face in the future?

2. Finishing: With the split face panel ledger being natural stone, the thickness varies from piece to piece from 1/4" to almost 3/4". In some places it will be flush with the porcelain and in some it will stick out. I’m not so concerned about this transition in particular, however is there any way to ensure a clean looking finished edge on an outside corner / drywall transition?
   
   
   

3. Thinset: Should I use 2 different types of thinset for each type of tile? Mapei, Custom Building Products and Versabond make thinset for all different types of applications: porcelain, large format, natural stone, different colors, etc. I’m lost in terms of which brand(s) and which specific product(s) to go with. Any direction here would be highly appreciated.

4. Grout & Sealing: The individual stones in the splitface panel ledger are either flush with each other or have tiny gaps between them – will it be possible and/or necessary to grout between them? On the backside there is some sort of glue between the individual stones, though I am not sure how waterproof that is.

5. Grout & Sealing: From my research it seems that the consensus is that it’s a good idea to seal slate before grouting so as not to stain the surface with the grout. However, porcelain can be sealed after grouting (I plan to use GlazeGuard porcelain specific sealer to give it that "wet" look). What would be the best approach here? Pre-seal slate, grout and then seal porcelain & grout?

Thank you in advance for any guidance!