I have a 2927ax fully configured with 2.4GHz guest and non-guest SSIDs, 5GHz guest and non-guest SSIDs, and VLANs on the physical ports. Been in place for a while but Wi-Fi coverage in my modest house is poor. So was looking to turn the 2927ax on the ground floor into a mesh root, and add an AP 906 node on the top floor. I have read manuals and various mesh guides but still confused! So...

Will the 2927ax mesh root still be able to directly connect to laptops and phones via the same SSIDs, or does turning it into a mesh root disable the 2.4 and 5GHz for normal Wi-Fi?

Following on from above question, is the AP 906 able to connect to the mesh root wirelessly (can't easily get a cable up the stairs), and broadcast the same (existing) SSIDs?

Please excuse the dumb questions but the AP 906 would be an expensive purchase for me and I certainly can't justify having to buy 2 mesh nodes.

If the 2927ax is acting as the mesh root then it will still behave normally as a wifi "access point", the mesh makes no difference.

Whether or not the AP906 will connect wirelessly to the 2927ax depends on the distance and any obstructions between them, as per "normal" wifi behaviour. If your devices e.g. phone can "see" the 2927ax from your proposed AP906 location then you have a fighting chance I guess.

SSID's etc all remain as they are, in mesh setup you have a "Bridge VLAN to mesh" option, although mine seemed to do that anyway before that option appeared in later firmware.