You can pretty much rule out laser power transmission from orbit. It would not get through a dust storm. I don't know how dust affects microwave.
I hadn't thought of multiple satellites. That could be an option later, but the trouble with low orbits is that they have night time when the target has night.Secondly, an electric thruster needs about 6km/s delta V to go from high earth orbit to high Mars orbit. It then needs about another 1km/s to get to Mars stationary orbit, and perhaps a further 3km/s to get to a low orbit (without looking up Mars orbital velocities).With lasers, the space system is "down scalable". Every electric thrust mission that arrives could just park itself in Mars stationary orbit (the primary cargo would be released well before orbital insertion for direct entry), and operate independently. If after a few years there are five 200KW arrays, they can all point at the same surface array, providing excellent redundancy.