Ember tetras can be pretty tiny and gardneri have very large mouths, may not be a good combo.
With killies and puffers, you can pretty much be assured your guppy tails are going to get shredded.
Also, be aware that mileage varies greatly between individual pea puffers. Some are pretty mellow (like what you have), and some absolutely can not live with other fish. So while the ones you have may be ok, be careful about adding new ones. Also make sure they have plenty of snails or you are target feeding because they can have difficulty getting to the food in community tanks ime.
You can/should do a larger school of pygmy cories. They (like all cories) need to be in groups to be comfortable. I'd say absolute minimum of 6, but they're so small and are your only bottom level fish so I'd say you could easily go 12-15. I've got 6 in a heavily planted 10g, and I don't even see them half the time!
The other poster already addressed the dwarf gouramis. Sometimes two males can coexist in a tank, but often they can't. I've heard a lot of people say the dwarfs are the most aggressive gouramis there are (at least as far as inter-species aggression). Also, they occupy the same part of the water column as your gardneri and australes (I've had both, as well as the dwarf gouramis), so would make for a really crowded upper portion of the water column. I'd honestly probably just skip the gouramis altogether.
I have gold rams (in very much less than ideal water conditions - ph of 8.3, kh of 18) and they are some of my favorite fish, highly recommend them. Also highly encourage you to get them from a reputable breeder as they'll likely be a lot hardier and a lot more colorful. There is a really good one on here occasionally and also a couple I know of on AB.
Only other comment is that I'm sure you know this, but a week is not long enough to cycle a tank - especially with aquasoil. A lot of the fish you're talking about can be a little pricey and/or a little sensitive to water conditions, so do your water tests and make SURE the tank has gone through the full cycle and is stable before you start adding these guys in.