(1) Yes, I would recommend just leaving advanced roaming parameters via the command line alone unless you are 100% sure you got a problem that needs to be solved. I found that most of the advice floating around in that regard no longer apply to devices made within the last couple of years. But if you do start fooling around with the CLI, make a note of all the things you changed — there's not an easy way otherwise to remember or restore things to default short of factory-resetting the AP's.
(2) I would recommend turning the power up to full (the default) unless the two AP's are really close to each other and / or need to share the same channel. In Ruckus's ZoneDirector manual, they have some best practice guidelines, and they (roughly paraphrasing) recommend that ZoneFlex AP's be set at max power because BeamFlex inherently reduces interference compared to omnidirectional antennas, thanks to their ability to direct/focus energy in the direction of the client.
(3) The ability to check for updates from the web admin interface hasn't worked for a while. Nowadays, the way to check is to go to the Downloads page for your AP from the Ruckus support portal:
https://support.ruckuswireless.com/products/68-zoneflex-r500#firmwaresStandalone firmware is supposed to be downloadable by all members with accounts, even those without support contracts. If you encounter a standalone firmware that you cannot access, either file a support ticket or post something here. Historically, that's all it's taken for someone from Ruckus to fix the access controls.