ester
Not slacking multitasking
Do you mean the feed I've cited is a short list? If so, it's really not. Alfalfa rarely suits anything, so that cuts out a huge amount of feed. Everything from baileys, spillers, topspec, d&h contains either alfalfa or molasses or treated straw. If you want to give your horse the very best chance of doing well barefoot, then diet is critical. A small number can cope with anything but most need an optimum diet to do well, so it's worth starting out in that way.
Yes, plenty of others are appropriate.
I did give my horse the best chance barefoot, diet is critical and initially it didn't involve anything on your list apart from linseed. He has never been expected to cope with 'just anything'.
Funny I've found lots of other feeds available that just contain grass outside of your list, including some of the brands that you list.