Evaporative won't have ducts downstairs.
Multiple Split system is another good option. But please plan ahead and get external GPOs done by builder on exact locations.
Otherwise you will end up conducts running over your bricks all around the house. Henley quoted us around $400 for each GPO. We decided to skip. $1600 for 4 GPO was too much.
My only issue with split systems is their installation cost. They are charging between 800-1000 for each unit. If I'll go with 4 splits, it will cost close to $4500 (units) plus $3500 (installation).
So the refrigerated add on was another $8k for your house on top of the upgraded heating unit? That sounds reasonable. I will check with Henley on this.