I am in no doubt that the moment a SIM is inserted into a phone and it's switched on that the activities you've outlined happen—and all that gear you've mentioned then "has your everything in the database". For my purposes, that all that gear has soaked up info is essentially irrelevant (as it's going to happen anyway the first time one makes a call).
If I was being rigorous (or up to some nefarious mischief) and did not want any of that data to leak (at least until I was ready) then I'd disconnect the phone's antenna and/or conduct the work within a Faraday cage to stop the the radiation. Also, there are other details and steps I'd take but I'll deliberately refrain from mentioning them.
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* "I'm pulling these all out of my curious nerd memory so lots might be missing, outdated or unbalanced."
Ha, right. Then even if you're not fluent, I reckon you'll be familiar with all those books/standards that deal with such matters—ones that just about put Encyclopaedia Britannica to shame. Seems to me no normal human (even propeller-head nerds) could retain all that detail. :-)
... and SIM has valid certs, GPS time is synced to few split seconds, your eNB tower-your Uu up/down freqs, timeslots are assigned and mutual auth is passed, cyphering(can you believe it? "encryption" and "cryptography" are apparently deliberate word choice to light up normies, "they" proper say "cipher") is set up, HSS(heard those are Oracle DB) through MME is accepting your IMEI + IMSI + credentials, HLR has your location, VLR has you mapped to operator's home EPC if you're roaming, your IP address is assigned(LTE is all IP), PCRF is configuring your QoS stuff, S-GW is routing your packets to P-GW, your IMSI-IP map is sent to SMSC and SIP sessions for VoLTE call signaling as well as for SMSC is up, your BS(eNB) is maybe aware of your location, speed, direction of your movement for handover purposes, and by the way one of many accounting database somewhere in there probably a table referred to by HSS says your contract is not valid as far as it knows when and only when you try to request something paid. (I'm pulling these all out of my curious nerd memory so lots might be missing, outdated or unbalanced.)
So yeah testing a phone with testing SIM works... Just a few dozen Oracle Cisco Huawei Ericsson Nokia Alcatel gears has your everything in the database.