Gotcha. Make sure you use treated lumber, not much ventilation under there. Good luck.

Here's some information on deck blocks. Just remember it might feel like going backwards to return items/ rework your plan but in the long run a solid built deck will be worth it.

https://decksbye3.com/are-deck-blocks-a-good-idea-and-bad-plus-installation/

What's the load/ weight your putting on this? Usually the load is supported by beams running 90 degrees to the joists.. I can't speak to this plan, I've never built one like this but it doesn't mean it's wrong..

Unless your installing on concrete you'll want to make sure all 20 blocks are level and even with each other. That can be a pain but depending on skill and terrain. But if you're going for a low profile look than this might be better than buying and burying adjustable pierpads. Good luck!

One option if not wanting to mess with the jack stud is to offset the shower valve and have a ceiling mounted head. Just a thought.

There's lots of different levels of DYI. If you're a novice that may have replaced a light switch before, I'd be tempted to buy a new GFCI and replace it. If it doesn't work you can return it, if from a big box store and call a professional. Everyone's different. Just find your confort level, and put safety first. Anyone doing even minimal electric work would benefit from a $20 electric tester to confirm the circuit is dead. Good luck

Also here in WA, I believe you don't need a permit for a deck not attached to the house. If that were the case I'd negate the first beam. If you're, worried take a detailed drawing to a builder and they might give it a once over for you.

That's too much over kill on the pierpads/ deck blocks. For 16' you should have 3 pads/ blocks on each doubled up 26, 2 towards the end and 1 center. I would add a double 26 beam in the middle for added support/ to help bounce or defection. So imagine the beams going the 16' length, two where you have them at the top and bottom, one in the middle. So 3 -16' " beams" or double joist, and 9 pads total for a rock solid foundation.

Also if you add butyl tape/ window flashing that comes in rolls, on top of the joists where the decking meets ( on top of the 2*6 where you screw the decking) your joists will last a whole lot longer.

That 3 beam setup would be strong enough for most environments/ weight.

Here in WA if the deck isn't over 30" off the ground you don't need railing.

Also they sell concrete blocks/ pierpads with an adjustable 4*4 metal bracket so if you mess up a cut or the ground settles, you can use a wrench to adjust it up and down. Good luck..