hAP ac Lite is a perfect fit for this. (I even power it with a MQS and power bank) as Repeater (pseudo bridge) or just station (with NAT & masquerade) depends on what you want others to see from your network.
Sometimes I combine it with the mAP Lite on ether5 as WAN port, because in the mAP Lite I do auto detection of all my known networks as repeater and also make VPN connections to my home "TURN" server. Turn server is a hAP Lite @home (the cheapest box) found via DDNS that combines all my VPN connections.
It could all be combined in just the hAP ac Lite. With the hAP ac Lite you always have an active AP even as the other band is used as repeater and still searching for the AP to connect to.(what is a potential problem with the mAP Lite)