Definitely looks like a bryozoan (should be a completely harmless filter-feeder) on the right side of the pic; the part in the middle under the barnacle is tough to make out though.
Sorry, things have been a bit hectic for me lately - I agree with bryozoans. They typically look very neatly organized, whereas colonial tunicates look organized but disorderly, if that makes sense.
The bryozoans you found there look like a pretty good guess to me, OP. As mentioned, cool find! I’ve heard these tend not to do very well in aquariums (which makes sense, given that they’re NPS), but they should be harmless/beneficial while they last.
Edit: I knew I had a paper on these guys tucked away somewhere. If your friend wants to try feeding them (or to try growing them):
“Common microalgal genera used for feeding bryozoans include Dunaliella, Rhodomonas, Tetraselmis, and Pavlova. It is important to supply appropriate cell concentrations of the cultured microalgae to the bryozoan tank, taking into account the dilution volume of the tank itself. Feeding can be done by manual daily additions of cultured cells, or ideally, by a drip feed system, which can be applied both to closed and flow-through systems.”*
Feeding them where they’re at could be a bit tough, but you might be able to target feed them, or you might be able to setup something like a little tube with a funnel that drops the phyto out nearby for the bryozoans to feed on (they make a little current by beating their feeding tentacles - their lophophores - and that current brings the food to their mouth).**
*Source:
**Source and just some cool info about bryozoans:
Collecting and Culturing Bryozoans for Regenerative Studies
Among marine invertebrates, bryozoans are small, not well known, and complex to identify. Nevertheless, they offer unique opportunities for whole-body generation research, because of their colonial, modular mode of growth. Here, we describe detailed methods for...link.springer.com
