As ever, so much depends. Comfrey will become a fairly large plant with broad leavs, meaning it is going to shade out and push aside others that are too close. Alfalfa can produce massive quantities of roots, reaching deep, but can also be hard on neighbors. Something about alleopathy with. alfalfa too, I seem to recall.
Any particular reason you don't have dill on your herb list? It is on mine
Bush beans in with comfrey and alfalfa - I don't see the beans fairng well with that competition. Both of the others will grow taller and shade out the beans.
I might recommend looking into cover crop mixes, where some of the research is suggesting mixes of ten or more varieties.
It also matters what scale you are planning for. Is this for acreage, or for garden beds? Different choices make sense on different scales.