@Sarah977 Actually the guests full name and phone numbers are still there just not on the inbox reservation after 2 months. You need to go to Transaction History and click on the green payout amount. The you click on the reservation ID ie. HMNXXXXX and you will still see the itinerary for the trip with all the information. Of course I don't relay on this method as it could disappear at any time based on AirBnB's history, but currently it is available.
@Laura2237 I really do not recommend long term stays especially for new hosts. It's best like @Sarah977 says to limit the occupancy time to shorter stays for a few reasons. The number one reason is you are giving them tenancy rights with bookings over 27 days and you could need to evict them if they won't leave. The next big one is if they are a crappy guest it's going to be hard to get rid of them and you are usually stuck with them for the duration. At least if it's a short term guest you only have so long to have to deal with them.
You are not going to be able to speak to the guest until they actually book, this is a problem that has long been an issue with hosts. AirBnB will not give the number because their service fee's could be in jeopardy if you and the guests agree to an off platform deal for booking, so getting the number in advance on AirBnB is never going to happen. If you are a Preimer Partner on HA/VRBI you get the number in advance, but they do not allow single rooms there so it's of no value to you.