1. Does the SR2148P come with ears (or rack mount included) or is it an extra SKU? 2. Any hints or tips for our first SR2148P deploy with a customer whereby we have multiple AP330s and AP370s with them already?
All Aerohive SR series switches (SR2024P, SR2124P and SR2148P) ship with ears for mounting in a standard rack.
Regarding your question, that is a pretty open ended topic, so I'm not really sure how to proceed. If you have any more specific details I could provide you with some suggestions, but as far as connecting Aerohive APs, they will function pretty much the same as any other vendor's switch. Configure the SR2148P uplinks to the APs as trunk ports with the desired VLANs, PoE is enabled by default, so if that is not needed, disable it. I could go on, but without any details most of my suggestions will be easy ones :)
I'll take a stab at your second question. You probably want to setup a new network policy so you can create new device templates. Additionally, assuming you want this to only perform L2 functionality, set the policy for only switching. That way when you go to configure vlans and trunking, you won't need to associate any addressing, other than your mgt interface. I hope I went in the direction you were headed with your question.