So I just purchased a couple pounds of seed that is: "A mixture of ryegrain, vetch, fuba bean and red clover".
It doesn't specifically state that its been inoculated... I know that different plant families need different types of inoculant.
For this mixture what inoculants should I use?

I'm in Southern CA, zone 9 or 10... Any other covers I should consider for my area that might be better green manure/ nitrogen fixer? I've got heavy disturbed clay soil and I'm trying to start building it for future growing...

Thanks!

The type of inoculants vary a lot, and you might not even need any, depending on what's in the soil already. You might consider checking with your university extension service -- when I did, I found out the necessary bacteria were/are there.

The inoculant is more useful when you sow something "exotic", because the right bacterias are not there.

About clay soil, I suggest the japanese (i think) daikon radish that has a very long root. It is said to be good to brake the soil and leave some organic matter deep in the soil. Cut before flowering.

Rye in your mixture will do a good job too!
If there is fennel around, it has good long roots too.

When climate allows it, I am very fond of vetiver (does not stand frost nor shade). The roots are veeeeery long and it can stand dry and water.
It can stop running water when the soil is too dry to suck it, and prevent erosion.
vetiver.org
It is also good mulch full of silicium.