LOL I am loving that you are giving it so much thought and effort. But yes, you should do it differently.
1. You want to expedite this process much faster, as in yesterday. We are near the end of April and you are already late. Spring is a good time to seed a lawn, but it is not the best time. The best time is early fall, but if you don't want to have to wait then do it now. Right now. This weekend. And it can all be done at once.
2. Don't worry about weeds so much. Competition with weeds is another major problem with spring seeding, so you are going to get them anyway, and lots of them. Some that you get will die out in the fall, and just wait until the end of the year to deal with the others. Then, you can practice weed control next year, but that cannot be done while trying to establish a new lawn.
3. So you make informed decisions on soil/loam selections and to help you calculate and balance loam and organic matter (compost), here is an article on [url=https://www.ladybug.uconn.edu/PUrchasingTopsoil.htm]purchasing topsoil[/url]
4. Seems to me the bobcat will do the job of mixing them up pretty well. I really don't think you need to rototill anymore. But that might be my bias speaking (I hate the thought of rototilling LOL). After you get it all down and graded, take a sample to be tested.
5. Soil compaction is not a good thing. You will spend the rest of your years reversing that condition for the sake of the grass because it naturally happens to some degree. So, you see doing it deliberately is not what you want.
6. If you roll after seeding, do it with an empty barrel. All you need is to ensure the seed has good contact with the soil. Pressing them deep is not necessary. Be sure to press them no deeper in the soil than 1/4 inch.
7. Yes, do remove rocks and other debris.
8. Straw is usually cleaner than hay. Hay is most often full of weeds seeds.
a. Omit Step 2 because you don't have a lawn off first. If you decide to spray existing weeds, you do it early as 3 days before seeding. You have to be sure to use the herbicide that contains glyphosate ONLY. There are some products on the market that contain glyphosate (Rounup) and other herbicide ingredients, but those other ones will prevent the grass from growing. Or, you can do this with an organic agriculture vinegar (which is 20% strength).
b. Omit Step 3. If the weeds are high when they die, just mow them down. You don't have to dig them up. You can if you want but don't have to. The dead plants will decompose by themselves (just like your straw will do) and serve as good organic matter for the soil.
c. Omit Step 5 because you are working with newly grade soil that cannot possibly be compacted already. (Don't compact the soil, remember?)
10. Here is a great Kentucky Bluegrass blend for Massachusetts.
I call this the Regalia Blend
For purchasing all three from the same location, the only supplier I have right now is
Arkansas Valley Seed [url=https://www.avseeds.com/]avseeds.com[/url] 970-535-4481 (720-810-1666 for Brian)
Please let me know the price they quote. If I think it seems a little high, I have another supplier working on getting Kingfisher, so you'd be able to purchase all three from him if he gets it in very soon.
Please inquire again for yearly maintenance schedule once you get your new lawn planted.