Right, but the real Gunbird 2 game may not use the same sound driver program as the DSF rip. That would presumably affect if unaligned access occured or not. Try this: boot GB2, dump AICA RAM once it starts playing, and check for the driver version string near the top of RAM. Or alternatively, have AOSDK dump a RAM image, load that into Makaron, and see if unaligned accesses occur.
 Most DSF rips use version 2.50 because it's known where to patch that version so it doesn't clear the SH4 command buffer before reading it, and it's assumed the sequence data remained compatible. In order to be more accurate games should probably be ripped with the real driver they shipped with, but in practice that hasn't turned out to make much difference (Neill Corlett's Skies of Arcadia test DSF using the game's driver does seem to sound subtly different from KS's full rip using 2.50 but I could be hallucinating ;-)
I can confirm that the Gunbird 2 rip uses the same sound driver as the game. The sound formats it uses are actually incompatible with the ver. 2.50 driver.
Byte 4 in the 0x20-byte music data headers is an indicator of the sound data format, so there shouldn't be any major incompatibility issues using a different driver version as long as this value is same. The driver checks this value with what it expects and will reject loading sound data if it is different. Other than Gunbird 2, all of the Dreamcast games I've seen have a value of 2 for this byte (Gunbird 2 has value 1).
I've disassembled enough of the manatee driver so that I know how to modify the patches so that they work with different versions. I'll try Skies of Arcadia using the original driver and see if that helps things. The Skies of Arcadia driver is named bonito.drv, so there may be a significant enough difference from manatee.drv 2.50 even though they have the same sound format indicator.