I'm back with a bunch of questions! Hoping to get some help to decide on how I should proceed.

I'm in the process of setting up my new 15g tank and moving over the livestock from my big tank before taking it down. Right now I'm just using tap water. Since I'm using mostly amazonia (with a little controsoil cuz I ran out), I didn't want to start off with RODI water knowing that I would be doing so many water changes. But it seems that the amazonia is finally done leaching ammonia and my tank is finally done cycling. So I'm hoping to transition to using RODI water soon.

Right now I have 6 amano shrimps and 1 lone glofish danio all used to super hard tap water. (Last I checked it's like 8.2-8.4. kH and gH are so high that I lost count of how many drops.) I'm also doing pressurized co2 in the new tank, so it will be quite a big change for them. What would be the best way for me to go about acclimating them? I'm gonna do drip either way. But would it be better to acclimate them now to the new tank and then start doing top off with RODI? Or just switch to RODI and then acclimate them?

Will plants be affected by the switch to RODI water? The most sensitive things I have in there right now are probably the buce.

I'm also still trying to decide between doing RODI + tap, or just remineralizing. Not sure if/how each option would affect the switching process...

In case my stocking plan will affect anything: I'm planning on keeping a school of cardinal tetras, and possibly a small school of pygmy corys. The glofish danio will stay if it gets on with the cardinals, or I'll either rehome it, or set up my spare 10g tank for it. Also considering some neos (trying to decide between red or blue) in addition to the amanos.