This is one of the most difficult retrofits. The coffers require precise layout and you'll run into differences in where the ceiling joists are within that grid. The path of the cable between switch and blower may not be near where you need it. You need power to start the lighting circuit from somewhere. Lots of holes will be required to get wiring past the coffer without hurting it.

If you have carpeted rooms above don't rule out taking up the flooring for possible access and making use of a lighting control system with remote switch so that no direct wiring between the cans and the switch is required.

I,ve done more of these cans than I care to count. Basically, we locate two cans on each side of the room between rafters and cut out the holes and run romex between the holes on each side. We then use a very long flexible drill bit to drill through joists and fish romex to wire the four together. We then do the same thing to connect the wiring to a hot switch. As a general rule, we need to do very little cutting of dry wall.

I have the same exact question and situation as the OP. Would this project be any easier if the the lights installed were track lighting instead of recessed?

Thanks!