Yes, there are a wide variety of what amount to recipe books for different aluminum alloys along with their post treatment temperature profiles. Usually this includes details such as various impurity concentrations (more for steels), what temperature and time it is held at for each step of treatment, and processes like work hardening would be in there. There may be barriers to work hardening here but the heat treatment process seems like it should be similar to other casting processes.

At least I'd think so, sand and glass beads aren't terribly different.

I would expect that temperature and nozzle clogging would be where you'd see issues, with speed and probably small solid chunks causing bursts in flow rate since it's gravity fed. I'm sure they've thought of it... I'd expect it to be better than something built up layer by layer though, there's no messy attaching aluminum oxide layers to one another and figuring out a clean way to do it and then afterwards heat treat it properly all over again.