Just a question: does IPTV set-top box expect its data tagged or untagged (my ISP delivers IPTV multicasts via VLAN and set-top boxes expect them tagged as well).
Other than that … since all ports except ether1 are bridged, you can not configure vlans on ether3 the way you did. You’ll have to play with bridge vlan-filtering to make things work as you wish, there’s nice tutorial about it available. It should be fairly easy for you to get things right as you already have PPPoE over VLAN …
After you get your grip on VLAN configuration according to the linked tutorial, you’ll want to covert the setup to fully HW-offloaded setup, hAP ac has CPU which is not the fastest on the block but has a decent switch chip.