Currency is counted depending on what portions of the Lythian are duplicated and how many times.
In the case of a Heathen Haenym with two heads joined at the shoulder, you would claim Full Body for the main portion, plus an additional Headshot claim for its duplicated anatomy. If the Heathen is split lower down and has two torsos, then you would claim Full Body and Half Body. If your Treble Symphony has all three parts of its hivemind fully depicted in the submission, you may claim Full Body three times. But multiple limbs or other appendages, such as a Chuikha's taur half or a Kella Ser's living tail, do not count as additional bodies.
Additionally, when it comes to depicting these multiple parts in art, you do not need to have them visible in all the time, if it is logical for that specific piece. For example, a Lythian with two heads must have both heads visible if they are in a front-facing pose looking straight at the camera. However, if the same Lythian is depicted in a side-facing pose with the camera pointing at them from the left or right, the head further away only needs to be hinted at, eg, an ear sticking out; in this case, however, you wouldn't claim Headshot, since it is barely visible. If your piece features multiple Lythians or foreground pieces, it may also make sense for the head to be obscured.
The only exception to this are Treble Symphonies, which must have all three bodies at least hinted at in some fashion, such as a tail poking out from a bush.
However, you may use the FORMula Plus item to add a simplified, alternate form to your Lythian. For example, if you give your Treble Symphony a Natural form, then you can use their Natural form in submissions to avoid having to depict all three parts of their hivemind all the time. The same applies to any other characters with multiple appendages you may want to simplify.