Best plan for unfinished ETF renovation and filling gaps

I have reached the point of no return. This weekend I am going to put down my last section of ETF, using starter fert and frost cloth. I have a question around what to do with the remainder of the lawn that has not been prepared for seed (I have run out of time due to the season marching into winter, and an operation next week) this section already has weeds starting but established grass has refreshed itself as well, and I’m guessing there is still grub within the soil profile as I have not treated this section with anything as yet.

Any advice about what I could do to suppress grub and weeds but support healthy lawn to recolonise into the big gaps? I have all manner of unwanted pest grasses including kikuyu. Some areas are worse than others, as I did spray with tricolour a few times on the summer flat weeds and the kikuyu.

I was thinking to blanket spray with Gold? Any suggestions appreciated.

Would like to order products today so they arrive in time for application next week Wednesday.