My parents' house currently has a single 802.11b/g/n/ac access point. It covers about 2/3 of their first floor and 1/3 of their second floor. The rest is lacking signal. They want me to close this gap for them. Also, they have no cell service on their property and would like WiFi in their barn/workshop so that Mom can communicate with Dad easily when he's out there. I have already run ethernet out there to accomplish this.
I have three perfectly functional 802.11b/g/n (no ac) access points lying around. Because of this, the cost of using them is $0, which is important here. I'd like to use them, but I'm uncertain about the implications of mixing these with their existing 802.11b/g/n/ac access point. Some of their devices (phones/laptops/tablets) support only 802.11n, so I don't think those devices would notice the difference. But other devices support 802.11ac, and I don't know how they might behave in this environment.
Would there be negative implications for those devices to have some access points be 802.11n while one is 802.11ac? Would roaming be adversely affected / impossible?