Wireless (not BT) phones and more questions

Looking to buy a new phone system for our business. I have no knowlege of phone systems. We got used to long range wireless phones.
1. Can OBI1000 be 'paired' with a regular wireless phone so that both 1000 and wireless ring? 1000 and wireless can be easily 'conferenced' together during any incoming or outgoing call?
2. What equipment do I need to buy to be able to receive multiple calls on a single phone number? 3. Currently our phone company does 'line hunting' for us to route a call to an available number. Can OBI do the same?
4. Can all outgoing calls show our main company number in caller ID?
5. What equipment do I need to buy to forward voice messages to Exchange and/or Gmail box?

Thanks in advance.