I agree, Linckia multiflora, and luck you are! The best Linckia out there in terms of likelihood to live.
Biofilm is a mish mash of "stuff" growing on LR...algal/bacterial films and the microscopic critters that feed on it.
Linckia do not appear to eat algae in the sense we know it - hair, slime, macros - and they do no appear to eat detritus. Both of these are in abundance in younger tanks and yet Linckia do not survive well in such systems. In general, Linckia can not be spot fed.
I believe all Linckia can reproduce via arm drops but it is more likely in this species in captivity because it appears to be easier to meet its needs. It is far less common in other Linckia in captivity, becuase most are likely on the edge of survival and death by starvation at any point, and therefor do not have the energy reserves to regenerate.