[Worldbuilding] Help Me Flesh Out My Space Opera Setting?

[FDragoon]

In regards to the Mekkans base form it could just be a spheroid or ovoid and it adapts itself to either the host species or planet environment as needed
granted they need information ahead of time to accomplish the adaptation.
The current Mekkan Ambassador to Human worlds could look like the TMNT Fugitoid when first encountered but over time he/it looks more like a silver 3PO having watched Star Wars recently
or goes for the femdroid service units if it wants to identify as female

[Varyon]

Originally Posted by Phantasm

I haven't decided yet, other than "living robots"; they're currently humanoid, but lately I've been thinking about making them tracked or wheeled below the waist, with less human-ish features above. (I'm not even sure Cyboria, their home planet, would have an atmosphere, given its distance from the star that captured it.)

Given you've stated they were created rather than somehow evolving naturally, we want to look at utility. Wheels make sense because they are an extremely efficient means of locomotion. Legs make sense because they let you go just about anywhere. Maybe something akin to the Tachikoma from Ghost in the Shell: Stand Alone Complex, where they have legs that end in wheels? Alternatively, you could play up the Transformer aspect by having wheels along the front or back of their lower legs - when they've got even ground to work with, the legs kind up fold down to the ground and they use the wheels for motion.

Alternatively, work out what their makers looked like, and base the Mekkans on that.

Of course, if they can rapidly shapeshift, something like a shapeless blob that simply grows the structures/features it needs as it needs them would be an option.