As put in Cisco Networking for Dummies article on Multiple SSIDs with a Single Access Point (AP) (link) The Service Set Identifier (SSID) defines what is thought of as the wireless network. So if you ...
Yes, you can. Computers in this case are in the same network, and they can communicate with each other through the AP.
No , TTL is an 8 bit field so it can't be more than 255
Trunk against Access --> Access the frame will not be tagged, it maybe will be dropped ,the messages from a vlan to the same vlan will arrive.