Heaven: If I just 'paint' this on the leaves of the plants instead of 'spray' do you think I can then plant grass seed later? Maybe I'll just test a small spot.
We often paint the leaves of an encroaching species on our putting greens at the golf course. If you have a stoloniferous turf (bermuda, creeping bent, zoysia) you won't need to reseed. Just give it a few days or weeks to fill in, depending on how large the invasive patch.
Doing a small test spot is always a good idea.