I wouldn't put any rainbows in a 10 gal, especially Bosemani's which get to about 4 inches long, simply because they is not nearly enough space for swimming and they are very active.
Could try some of the fish listed below you don't need to add salt necessarily for the platies I have three in my 36g and they are doing fine with no salt added.Good tanks mates for these Gouramis: All Barbs, Gouramis, Danios, Rainbows, a school of Clown Loaches, one Red Tail Shark or one Rainbow Shark, a school of Bala Sharks, and a Spiny Eel. Click here to read more about several other groups of compatible fish.
this is where I got the salt thing from
Common Mollies are the Black Molly (which was derived from the Marled Molly - Poecilia sphenops) and the Sail-Fin Molly - Poecilia velifera (of which there are also several color varieties available). Black Mollies need at least one teaspoon of salt per five gallons of water to keep them healthy and prevent the outbreak of ``ich'' (Ichthyophthirius multifiliis, a parasite commonly seen in aquaria) while Sail-Fin Mollies need at least three times this amount. Sail-Fins grow to 6" while Black Mollies stay less than 3".
Closely related, Swordtails - Xiphophorus helleri and Platies - Xiphophorus maculatus are also popular fish. A number of color and finnage varieties are available of each with some of the Platies also referred to as ``Moons''. These fish need at least a teaspoon of salt per 5 gallons of water to be healthy.
Also, I thought I read that if you have gourami's you should only have one male, but I just read this in one of the links above from Playtetrafan
Most Gouramis live best in a group with at least 3 males, and about twice as many females. So you might decide to order 3 males and 5 females. One male and one female, or two males, is not a good combination.
Try 6 inches! Bosemanis need at least a 50 gallon tank that is 4 ft long. As mentioned before, they are active and should be in a school.Bosemani's grow to approx 2 inches.
Not sure where this came from, but from what I've read and my own experience a 1M/2F ratio is best. Lots of debate about Gourami though.