If you use an actual SoC such as the Qualcomm Snapdragon Processor for mobile communications would it be possible to have two cores both sharing a common IO (Cellular/WiFi/GPS/Bluetooth) integrated circuits but its own separate antenna ?
I believe that's default. All cores share resources (IO being one of them). Each of the cores wouldn't have their own antenna though, no. Wifi/Cell/GPS/Bluetooth may have their own antenna though. There's no point in duplicate antenna for two different applications because one would cause so much noise on the other one that you'd never be able to receive anything besides what the other antenna is broadcasting.
Instead, the standard way to do multiple things on an antenna is to do TDM (Time division multiplexing).
RF protocols using the same frequency will interfere heavily, regardless of the number of antennas, so the best thing you can do is implement them in the same place and try to coordinate the services, for example by delaying outgoing Bluetooth frames while a WiFi packet is being received, because starting a transmission would interrupt the active transfer, and probably not manage to send out a packet undisturbed.
For protocols on different frequencies, you can use analog bandpass filters to isolate the different transceivers. Whether you use the same, or different antennas does not matter that much then -- the antenna geometry must match any frequency range you plan to use.
In order to reach different frequency bands at the same time, you need multiple transceivers anyway -- while it is possible to build a wideband transceiver, this is ridiculously expensive and gives worse performance, so it is uninteresting both from an economic and an engineering point of view.