Microfluffies are (in my headcanon) not different from regular fluffies, reproduction-wise. They form families and larger herds, may have a higher metabolism and faster reproduction cycle, but do not produce different castes like ants, because they are still mammals, and I’ve never heard of mammals producing different offspring or having just a single (or multiple) “breeder/s” per colony.
But that’s just my unimaginative headcanon. I find the idea very intriguing, since I’m keeping ants as a hobby. Why not have a single queen fluffy (“mummah fwuffy”), who can produce different fluffies based on hormonal factors, like workers (“diggy fwuffy”, “nummy finda fwuffy”, “babbeh cawe fwuffy”) and soldiers (“toughie fwends”)?
There is a comic by Muffin, where she follows the life of a ant microfluffy, might be an inspiration (if you haven’t read it already):