2 pitbull plecos is a fair bit still for a tank of that size - they produce a lot of waste, so with only 1 then you could have a few more fish. I also have found them not to be massive algae eaters, and fairly shy, along with clown plecos. I'm not sure about bristle nose plecos as to size suitability, as they are allegedly good algae eaters. I can't speak from experience though as I've never kept them.
Ottos aren't necessarily sensitive, they just have a nasty habit of dying for no apparent reason! I have 2 in my 180L though and I'm looking at getting a few more as they do do a great job of algae cleaning.
With dwarf gouramis, watch out for aggression as the colourful ones are the males, and if they don't have space to figure out their own territories, you could end up with some aggression. The silver coloured ones are females, but I wouldn't recommend keeping a male and female together. They should only come together for breeding as otherwise the male will constantly hassle her. 2 females would be fine, but they're not as pretty...
X-rays may also be nippy to the gourami, depending on how gutsy he or she is
Some nice tetras include emperors, lemons, columbian, glow light and rummy nosed. Other nice shoalars include harlequin rasbora, danios, pencil fish and thread fin rainbowfish.
If you're not dead set on a tetra-type, there are some gorgeous guppies and endlers going round these days, as well as some really nice mollies with veil tails and sail fins. Bear in mind though that mollies do benefit from (but don't necessarily need) a bit of salt in the aquarium, and so it's an idea to check compatibility with other fish first.
If you're not hard set on a gourami for the main fish, then there are always peaceful cichlid types like apistogramma and badis (dario dario) which are beauties!
+1 for the amanos - I love watching mine go around picking up food with their little claws and feeding themselves. Great entertainment.
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