New to the Hobby and Looking for Advice on First Aquarium

[Byron]

I can only comment on the freshwater setups.

Freshwater Tanks:
Option 1
Planted aquarium with a bunch of neon tetras, a couple cherry shrimp, maybe a corydora, and coolie loaches.

No problem with tank size and fish here, but water parameters may be. If you use your tap water it is too hard for these fish. But if you do go to RO entirely or as a mix, this will solve the GH and pH issues for theese fish as they are all soft water species. [Shrimp, not sure as I do not keep them] I agree with JuiceBox52 on the numbers, you must havee groups of shoaling species like neons, corydoras [and by the way, the name is Corydoras whether singular or plural] and loaches. And Corydoras and loaches should not be combined.

Option 2
Planted aquarium with Pseudomugil, Neon Red, fork tail rainbow, a couple of neon tetras, corydora, rasbora, cherry shrimp, coolie loach, praecox rainbow.

Neon tetras, Corydoras, rasboras are all shoaling and thus need groups, and obviously the same water parameter issue as above. The rainbowfish species are at the very top end of their range for GH and pH but better if the water is RO mixed. These fish too are shoaling, meaning groups, and i do not think all will work together in this sized tank. Here are links to data on the species:

Pseudomugil gertrudae – Spotted Blue-eye — Seriously Fish

www.seriouslyfish.com

Pseudomugil sp. ‘red neon’ (Pseudomugil iriani, Pseudomugil cf. paskai) — Seriously Fish

www.seriouslyfish.com

Melanotaenia praecox (Neon Dwarf Rainbowfish) — Seriously Fish

www.seriouslyfish.com