Advice on Some Upgrades?

I have a 9 gallon tank for Cowboy. I cycled as recommended, levels have been perfect and checked daily (sometimes twice a day bc I’m paranoid) and everything is good, zero concerns so far. That said, I did not know that I would become obsessed with the idea of aquascaping when I went for dog food and came home with a tank and the idea to go back for the saddest guy on the wall of sad cup Bettas. Over the past weeks since having him home, I have been doing so much lurking on this sub and seeing all your beautiful planted tanks and how happy it makes your little guys. I have decided that I will be giving this dude an upgrade. I did get some advice for the transfer of him to a holding tank and know not to clean his filter, to preserve his water, and ensure his temp home is heated and safe while I build. I also did a tonne of research on picking safe hardscaping and driftwood and how to prepare/treat it in advance.

The plan:

1. Transfer him with his current water, heater, and floating cover plant cuttings to a temporary vessel (5 gallon ok for a few days?) to ensure there are no abrupt changes to his water.

2. Drain the tank, while moving current gravel to a container with some of his water so I don’t lose the bacteria (I could also place it in a mesh bag in his temp space and use it as needed for rescaping). I just don’t want it to dry out our lose its benefits.

3. Hardscape with inert rocks (found quartz, soaked with H₂O₂, boiled and scrubbed). Add my found wood (all passed a boil test to ensure species are hard and free of any sap), which have been boiled and soaking in water (changed every second day).

4. Purchase some new plants, which I will dip in H₂O₂ and rinse to avoid pet store contaminants or sneaky snail eggs).

5. Lay out the tank with bio-substrate in area where I’ll be planting, add gavel and aquarium sand on top and finish rest of floor with combo of sand and gravel.

6. Place and secure plants.

7. Add my new custom lid (clear acrylic with hinges cut and designed to allow separate acces to filter/back area). This allows me to use a light for plant growth.

Some notes:

1. My house uses gravity fed mountain creek water (consistent ph of 6.5). The creek supply is fresh, fast and always crystal clear. I use a whole home filter system to remove any possibility of contaminants. I say this bc it’s important to note the water is not chemically treated as much tap water is.

2. Priority is to provide plenty of swimming space, hiding spots (he’s alone and will remain so unless I end up getting a larger set up in the future. Lots of resting spots close to surface (he loves his partially submerged plant cuttings for this). Ensure resting spots are not disturbed by filter flow. Having plant substrate only in designated section to avoid disturbing during gravel cleaning.

My questions:

1. For the new lid - I expect condensation to be prevalent, but have you noticed any benefit to adding holes for air flow?

2. How are we feeling about viewing towers? Do Bettas like them? Are they tacky? I could custom fit it with my lid build, but debating if I like them. I think Cowboy probably would though.

3. When adding water back to the tank… if Cowboy is in his holding vessel with his current water, how should I go about filling the new tank to let it cycle/settle for a few days to ensure all the scaping hasn’t made my levels unsafe?

4. I have Seachem stability, maybe using it to fill half the tank, letting it run (how long) then adding back in half his current water to top it up? Give it a day, test, then move him and the rest of his water into the new tank?

5. I’m tempted to go the way of a tannin rich environment. Any thoughts on which plants to avoid if I am going to introduce leaf litter? Or should I stay away from this for now?

6. If I do this over the span of 3 days, ensure temps are right, levels are perfect, properly acclimate Cowboy when reintroducing him, will that be enough time for things to settle in the new environment?

7. Tips for beginner friendly plants?

8. Favourite/accessible glue/string for securing hardscape and plants?

I only plan on doing this once, so I want to do it right! Any tips, things I might be overlooking, etc. are so appreciated!

Pics are of his current lame house - a mansion compared to his cup but still not enough. Inert and treated rocks and driftwood pieces, substrate I plan on using for plants.