[EDIT] solved the global settings with mesh question, working on a couple others [/EDIT]

Setup: I have a Unifi 6 pro and Unifi 6 LR in a 3,000 foot 2 level home in moderately dense urban environment. The LR is the Child node & connected by wifi only (no cable available) and the Pro is the Parent and is wired into the gateway. Use: work (zoom, etc.) downloads, video streaming, web browsing. 3 users all tech/programmers. Gaming currently not important.

Goals:

A. Solid connections for all devices throughout the house

B. High bandwidth, especially for 5 ghz clients near the Pro AP - these regularly do large downloads.

C. Seamless roaming between the APs is somewhat important (not essential but nice to have)

Questions:

Q1) Multiple wifi networks were auto-created. I disabled all but one, is this the right move? I don't think I explicitly made all these networks, they came out of the setup process.

https://preview.redd.it/8uautu4bwwra1.png?width=779&format=png&auto=webp&v=enabled&s=e8018a24d8270c0b611be656e04cca05e7bab146

Q2) Same channels? [[UPDATE/ANSWER: Discovered roaming is called "zero handoff" and yes you should have all using the same channel if they are using the same SSID]]

Q3) Can I mix/match 5ghz bandwitdh? I'd like the pro to be 160 and the LR to be 80, is that going to cause roaming isuues or other kinds of problems?

Q4) Orientation - I have the pro on the wall downstairs and the LR upstairs on the ceiling. Any concerns about this (polarization, etc.) Since the downstairs is the master I presume mounting it on the ceiling would limit the wireless connection between APs. cite: unifi radiation patterns https://help.ui.com/hc/en-us/articles/115005212927-UniFi-UAP-Antenna-Radiation-Patterns