Zebra loaches grow 3 to 5 inches and do best in groups of at least 3 so would not do well in a 10 gallon. You should not put gouramis and bettas together as they are related and may be aggressive to one another. I would recommend a group of 4 or 5 rasboras so you can see their natural behavior. You can have 1 to 3 otos in a 10 gallon depending on how many other fish you have, how much algae your tank has, etc.
I think one male dwarf gourami, 5 rasboras, and 2 otos would do fine in a 10 gallon with weekly water changes of 20 to 30%. You will have to supplement the otos with fresh veggies and algae tabs, I think. Do not overfeed. If you can, try to have some live plants and hiding places.
In my 10 gallon I have 1 male betta, 3 zebra danios, 2 harlequin rasboras (one jumped out and passed away over the weekend, very sad), 1 oto, and 4 dwarf cory cats. I do about a 30% water change every week. I also have a rather mild filter (penguin biowheel 100) so the current isn't too strong for the betta (as you would want to do for a gourami since they are also surface breathers).
Just my opinion...