As it's not going to be a razorr sharp 90degree corner anyway the only one worth pursuing is no.4.
Decent brush, decent amount of paint, make it ooze out a bead to form the edge of the colour & then drag/pull that along the edge say 6" at a time before recharging brush. Plenty damp cloths (micro cloth things are great) to remove cockups.
If you get enough paint on from the bead, you won't need to do a 2nd coat anywhere near the edge....