Well, that's not impossible.
In a heavily planted tank I'd go for dwarf cichlids, along with cories, smaller plecos or other catfish and some species of smaller schooling and peaceful fish, i.e. tetras or barbs and their relatives. Fine gravel would be fine. Oh my, LOL. Also some decorative elements like bogwood, stones or caves as a territory for the cichlids. The easiest thing would be to chose the different species according to the water you have, i.e. rams and many tetras like it soft and a bit acidic, others thrive in harder water with neutral or slightly alcaline PH or don't care so much. Some years ago, I kept Nannacara anomala along with smaller barbs, cories and clown plecos in medium hard water with PH 7.5, and many plants. They spawned frequently, but the fry got eaten by their tank mates in most cases.
With medium sized cichlids, I'd use less plants to provide them with digging areas around their territories, but you can use hardy plants for background and corners, plants that grow on wood or stones (i.e. java fern, java moss) and floating plants. My firemouths lived in a tank like that, along with a group of swordtails and clown plecos (still the same).
Be careful when chosing the loaches - clown loaches get big and might bother the smaller fish. Today I saw two that let the 5" oscars int the same tank appear as dwarfs.
Just my 2 cents.
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Gisela
moppel@gismo.owl.de