Sounds good so far but don’t underestimate the couch whose roots can live for up to a year under thick mulches, and sooner or later you will need to be on the case with your trowel, assuming you want to be permanently rid of it, which is possible, I am in that situation now.
At least the new growth of couch grass, from under a deep mulch, is much weaker and more sporadic than from unmulched roots, giving you a better chance of removing shoots and starving roots. Leaf mulch and grass cuttings is ok if you are setting out larger plants, not ideal, may attract slugs of weather turns wet.