At this point, as long as the AP/ENB is setup proper, you can use any core. (Disable LGW, set pointers as above, etc).
Our Telrad core needs the OPC and Auth codes preprogrammed into the HSS IMSI’s records. Once this is done, any sim card in any ue works, so far.
Unless Baicell has plans to change this, so far so good. I’ve heard rumors that Telrad wants the cross compatibility broken.