Loaches are social critters, so first off I'd get your lone loach some buddies. They need a school of 5-6 minimum, as they tend to have a hierarchy going. You'll get to see them play and tussle with each other and have more natural behaviors this way too!
As for the gourami, blue gourami tend to be jerks... With such a large size difference between your blue and your dwarf I'd worry the dwarf is going to be bullied until he stresses himself to death. Gourami can be kept in groups just fine as long as they're near the same sizes as each other and there's a maximum of one male in the tank. Mixing dwarf gourami with large gourami usually ends badly for the dwarfs... If you go the gourami group route, make sure you have 4+ to diffuse any aggression, and stick to the same species as much as possible. Different color morphs are fine (blue, gold, lavendar, opaline, and platinum are all the same species and get along with each other), but mixing things like a blues, pearls, moonlight, snakeskin, etc together is tricky. It can be done (my current gourami bunch has one pearl, 2 blues, 2 opalines, and 1 lavendar and they get along well), but is much more dependent on fish personalities and how you introduce them.
As far as other fish to go with them go, what kinds of fish do you like? Rainbow fish work well, as do cherry barbs, tetras (stick to the non-nippy ones, gourami feelers are too tempting), danios, etc. Your loaches will prefer warmer, soft, acidic water, while gourami are pretty flexible. Aim for community members that also prefer soft, acidic, warm water and you can't go wrong