Flying foxes are not "team players", similar to RT & rainbow sharks. They, like those sharks, don't mix well with similarly shaped fish or their same species. Siamese algae eaters only eat algae (& only some forms) when they are young or there is no other fish food available. With keeping other fish they will always get more than their fair share of food, they can get quite chubby. They also like to be in a group. You can keep just 1, 2 may fight a bit, 4-6 are happier together but dang, that's a lot of 5 or 6 inch fish in a 55g. There are prettier fish you can keep instead. Both BN plecos & Siamese algae eater eat & poo quite a bit...but of course you will be vacuuming out poo & changing lots of water every week!!! At least that "should be" your habit (with occasional lapses).
DO NOT get a Chinese algae eater, they are hard to find the right mix of fish where they will not be aggressive. They also get too large for most tank at 10 inches.
You know, spotted pictus cats were the reason I started keeping fish 40+ years ago. But after all this time I still have not kept any, ever, LOL!! It's always a case not this tank or not with that species.
So, to my understanding & opinions, you'd like 8 or 10 tiger barbs (color mixing is fine, they're all the same species, they know), 10-12 kuhli (pangio) loaches or more (I would go with all 1 species but at least 6+ of any 1 kind would be "ok" but they really are more fun with more!). & maybe a blue or gold gourami...my gourami love has faded over ther years.
If you really want a BN pleco (plecs are cool!) then go with only 8 or 10 pangio loaches & extra caves. If corys are higher on your wish list than a BN, then I'd go with 6-8 of the same species & 8/1species of loach but maybe skip the gourami until you know you can keep up with WCs & maybe more barbs would be more interesting than a gourami...You don't have to decide everything right this minute...