Usually when I transport stems (for Danny or whoever):
1) Vocals
2) Instruments
3) Guitars
4) Bass Guitar
5) Drums
Stems are whatever group you/I like to make.
For me, personally, its easier to group them within the project as 'folders' and "S" [Solo] the folder out (which keeps their respective busses solo'd) ... to export it as a stem
Of course, the 'master' (top-final) buss has no *mastering effects in the fx bin during export. Your third party probably prefers some headroom in each, like -3 dBs, I dunno.