Ok, just found the answer to my questions on another post. thanks.

I guess with organic there's little difference between fertilizer and soil amendment, it all does both i guess.

Alfalfa horse pellets won't go through a broadcast spreader but gerbil pellets might. Look around.

Alfalfa pellets went through my broadcast spreader, but not very fast, even opened all the way up. I filled my wheel barrow with the pellets and just walked around the yard stopping every few feet and spread by hand. Went much faster that way.

I have used a broadcast spreader to spread alfalfa pellets, but make sure get the small animal ones (for rabbits or gerbils). And even then they can be a tad bit too large for the spreader, so I wiggle and shake the spreader as I roll it across the lawn. Works fine for me.