Most warm season annual plots will fight weeds. First, I'd start wit your objectives. Are you working with enough acreage and trying to improve the local herd, or are you just planting for attraction. In general, summer plot are the best fit for folks in the south that are not near agriculture where native summer foods dry up for long periods and summer becomes a stress period. In the north, generally winter is the stress period you are trying to cover. I find warm season annuals the most difficult plots to have success with. The combination of weeds and browse pressure are a challenge. The best solution I've found (I'm south of you in central VA - zone 7a) is RR soybeans with a light mix of corn.
Beans and corn can be used in the north but with different objectives. Here I plant the beans for summer stress period forage and the light mix of corn is just for vertical cover to encourage daytime use. I don't care much about cobs or pods, those are a secondary concern. In the north, the pods and cobs are the objective to cover winter.
In most cases mixing warm season annuals is problematic. It limits weed control options. There are a few crops like buckwheat that are so aggressive that weeds are less of an issue.
It is too late to replant beans. At this point, I'd focus on your objectives for fall and winter and let that dictate you path.
Thanks,
Jack
