WDS between omnitiks and sxt

Please advise,
i have 3 omnitiks (in a line - central being the AP on a tower, the other 2 are clients to that omnitik) + i have 1 sxt that is client on the main omnitik.
i run normal 802.11n network on a regulatory domain freq, so that i have compatibility with mobile phones. this is not main usage but it’s very useful.
there is no need for groundbreaking speed on that link so that’s the reason for the setup being like this.

this is the 1st step which is ok and working. now i need the 2nd step and i don’t know how to do it, please advise.
now i’d like to put them in WDS , so that all of them can act as AP and that i get higher coverage for mobile phones.
is that doable?
omnitiks have level4 licence, of course. sxt lite has level3 licence, can it also act as wds device, or not?
if that is not possible, can the 2 slave omnitiks act as repeaters? do i loose any speed if there is no client connected to them?

I recommend doing this with virtual access-points on the side Omnitiks, but there is some documentation regarding repeater mode as well.
https://help.mikrotik.com/docs/display/ROS/Wireless+Interface#WirelessInterface-Virtualinterfaces
https://help.mikrotik.com/docs/display/ROS/Wireless+Interface#WirelessInterface-Repeater

Just put all Omnitik as AP bridge, with dynamic wds. Then i recomend to copy the dynamic WDS interface so it become static, rename it, and add it to a bridge. This is the old rock solid way of doing this, and if someone try to connect with wds, they are not automaticly added to a bridge.

This also make it possible to make a mesh network, if more omnitik connect to eachother. Then you may contoll this as meshed network directly in the bridge using horizon and or rstp with logical numbering.