If you cannot spray chemicals, there is nothing to spray for crabgrass. I suggest, as much as you can, hand pull the crabgrass, (actually, cut if off flush to the soil with a saw knife). Keep in mind crabgrass will be killed by frost about October 20th in our area.
If you seed, start about when temperatures drop below 85, about August 15 in our area. Seed germinates fast when the soil temperature is warm, (if you keep it moist).
Not sure, but heavy raking may remove most of the ground ivy--try a dethatcher rake. The stems creep and root as they go; a rake may catch the stems or rhizomes. Keep soil most so that the roots pull out.
Hats off to Canada for sending us some cool air this week. Thanks.