Yes, I know what you mean. I'm setting up new tanks and it can get very confusing because there is so much conflicting information on the internet.
The first thing I suggest is that you find out what sort of water comes out of your tap - how hard it is and what the pH is. I discovered that my water is naturally hard and alkaline, so I then looked for fish which did well, or didn't mind, those conditions. The ones that want soft, acidic conditions were immediately crossed off my list of possibilities.
Have you seen any fish that you like the look of? If you can pick out the ones that take your fancy, then look up to see what conditions they need, it gives a starting point and eliminates a lot that aren't suitable.
There were some good suggestions in my thread asking about stocking my 35-litre tank (I ended up getting a 75-litre as well, which isn't that much smaller than yours - some of the suggestions given for my 75-litre might suit your tank and might be something you'd like to have).
For bottom feeders, I've decided that I definitely want corydoras catfish. I love them. There are several varieties to choose from, some are hardier than others. I'd definitely recommend having a look at them to see if you like them. (You need to wait until your tank is well established before getting any of those if you wanted them, they like the tank to be well established and don't like changes in water quality that might happen when the tank is getting its equilibrium.)
I've got platies in my bigger tank and guppies in my smaller tank. Both are easy to look after, colourful and active. I like them. In my bigger tank, I've also got a small school (6) of pristella tetras. So, one possibility could be platies, tetras (there are lots of varieties and you might be able to have 2 schools in your bigger tank) and corydoras. But you'll have heaps of other options.
From what I've read, gouramis are top dwellers. You might want to look at the dwarf gouramis to see if you are interested in them.
Once you get some ideas, the knowledgeable people here can tell you if what you'd like will work.