**Always read the release notes of FW you're thinking of upgrading to**
The 7962 is by now an ancient AP, and might not be supported by the firmware you're intending to upgrade to. Answering _Part_ of your question, yes the Firmware for the ZD caries new FW for the APs. APs are then systematically upgraded, provisioned and rebooted. As for APs, I think that's more of a discovery and needs analysis issue. Do you have POE? how bout 30w of PoE AT? if so, get an R610, got a super dense concert venue you are trying to provide Signal to AND PoH? R720. I personally like R710's for their outstanding range and performance, and low-ish power consumption (PoE AT, 30w).
Best of Luck!