1. It's more based on the map/floor plans,you should design your ap deployment on: room size,floor type,conf area,open area's,outdoor Areas. (consider - that each room can have 4+ more devices working in the same time)
*try to figure from the client - how the lan infrastructure will be deployed - try to effect and build a smart lan infrastructure - if it's isn't designed yet*
2.Clearpss give u abilities to do billing in front of paypal and other methods as well.
*u may consider deploy nomadix GW for the guest vlan and connect it via Serial cable to the hotel PMS*
3.Airwave = Monitoring/Reporting/Alert/Design system (can also manage) , support multivendor
Clearpass = Smart auth /Access system (radius based) , support multivendor
Clearpss will fit your needs.
4.Sure :) Aruba Switches,Aruba controller + ClearPass
5. A lot :) , the QoS that your client want to give to each device,different service types,bandwidth, different services - check good the wall materials and other building infrastructure that might effect your coverage.
A POE is almost a must for hospitality deployment! Build a LANA infrastructure with 10/100/1000
I cannot write down all the know-how , but start simples with the floor plans + visual rf , be sure to fit the right wall materials.
And from there continue - based on all your client needs.
Regards.
Me