Sanity check mini split layout for old brick house
The way to go here is definitely the ductless mini splits. It sounds as though you have done your homework on this and you can always find what we call straight cooling units without heat. The mini splits are far more efficient than nearly any other system these days and you can choose which room you need to cool and how much it needs and when.You'll be glad you chose to go this way after its done.As far as stand by power, just unplug or turn off a breaker, but its not a lot of power loss either way. As far as over kill, you'll be glad if you add some overkill to an old home, they usually need it unless they are very well insulated and have great windows. Just speaking from experience.....good luck.