From what you were suggesting of your 6+ species only 3 would provide an extended supply of small seeds....
don’t see why they wouldn’t as the summer species would seed after flowering as well, they would be growing May - october and the autumn mix would be growing july - may
in fact on my plan there is actually 3 months where alh2 is actually on 66% of our farm meaning DEFRA get 15 months of value for a 12 month payment !