So after a full weekend trying to get the system installed (the easy part) and booting from hard drive (the impossible part until I replaced GRUB 2 with rEFInd), I’m able to (finally!) boot Haiku from hard drive.
It’s installed in its own BFS 32GB partition, no warning or error whatsoever during install. rEFInd detects Haiku, but when I try to install Haiku, almost every time I’m greeted by Haiku’s bout menu, and I must manually select Haiku’s partition (default is “None”). Partition is there and seems to work just fine. There is a “latest state” option along with a saved state from each of the few boots (just finished interesting last night before going to sleep). It started from first boot, so I guess the problem originated during installation. Or maybe rEFInd (installed later, because GRUB 2 wouldn’t find Haiku) broke something?