Hi ronski
To be honest, 27 series are old and not supported
I would opt for 2860n second user unit, and flash latest firmware. There about 100 give or take 10 or so
I think from memory another kitz user has a 2862, and posted over issues with rebooting or freezing but we have never had issues with 2860 or 29 series
It depends which series you go for, so you may have to set to wan2 and if wan1 (dsl) is not used, we usually disable it. You would also have usb 3/4 g if you have correct stick
Wi-Fi, there is no guest accounts but you do have 4 SSID you could create, and isolate from lan, vpn vlan etc so you could have 3 guest Wi-Fi or however you decide.
Also, if you do not have ipv6, goto hurricane and get a /64 block. Very easy to setup in draytek but it just works on 1 lan, not on all lan but you choose which lan
There’s more im sure and g3uise would hopefully post his thoughts
Many thanks
John