Crabgrass is an OK plant that withstands hard use in my Michigan paddocks. Grows low to the ground, spreads by seeding and runners. Horses will nibble on it, keeps the dirt covered to prevent erosion, water sheeting off in heavy rains. Seems to come back yearly no matter how torn up the ground gets! I know I have seen seed for sale, just can’t remember where. You could probably locate plants in the neighborhood, get them free for the digging! Mine never gets very tall, 4-5 inches at the most. I do mow off the tip ends and any taller weed seeds that sprout in the paddocks.
The mix looks OK, but not designed for MA the State. Maybe I am getting abbreviations mixed up? So many in use or localized that they are unclear (to me). I consider Mid-Atlantic area to be further south. Can you check your local seed MA State sources to find a similar mix designed to grow in your area? I say this because not all bluegrass or the other seeds, are suitable for all growing areas. There are lots of varieties within each grass catagory. Some will do better in colder locations, while others do better in warmer areas. Yet they are all still “bluegrass, rye, alfalfa.” You want seed that is designed for your growing location.
You did well picking perennial seed, not annual seeds. I personally would reduce the perennial rye percentage a bit, down to 10%. Something in my reading said rye was not that helpful in horse feed/hay. I will try to remember what. Buy seed that is labeled for planting THIS year. Older seed can be reduced cost, but seed viability is reduced with age. Poor storage (heat) in that long time can further affect seed fertility in a bad way.
I would NOT plant any clover. Horses and clovers “have issues” if there is much to be grazed. Red clover can cause slobbers. Alsike can cause photosensitivity on horses with white trim, AKA “clover poisoning.”
You will likely get some volunteer clover seeding itself in the fields, it just happens. That will probably be all the clover you will want or need to add a bit of Nitrogen to the soil. I mow pastures regularly, so any red clover is short, never gets the fungus going.
If your dirt is clay, you might consider planting Birdsfoot Trefoil, a form of alfalfa. It is not nearly as touchy as alfalfa, “grows well with others” by not killing plants around it, as alfalfa does. Handles the wetter ground of clay soils well, better than straight alfalfa will. Same benefit of adding nitrogen to the soils. Our horses like to graze it and it will spread seed for more plants, yet not take over the fields. It is a perennial.
If you can get seed spread, rolling the ground with a cultipacker helps seeds get soil contact for better germination rates. Spreading on damp ground should help. You will get seed washed away if it rains very much after spreading without the cultipacker. I have used a chain harrow when broadcast (3pt cone shaped broadcast seeder) seeding on dry, turned soil. This let me only drive on the land one time, seeding and dragging to cover the seeds. I do not have a cultipacker, so dragging was better than doing nothing. I got a pretty good germination rate on the new field.
Good luck!