Keep in mind that an AHJ inspecting your installation will use his interpretation of the NEC, and citing telecom standards for why you did or didn’t need to do something might be an uphill battle.
1) With the GEC (TBC for telecom) only entering a ferrous metal enclosure and otherwise running without raceway, I don’t see where Code (AHJ dependent) or Standards would require anything (or if there is even a performance risk). Probably no one will care what you do (within reason and otherwise within Code). If the GEC (TBC) had both entered and exited a ferrous metal enclosure (passthru) I’d say yes that requires bonding to the enclosure at entrance and exit locations with a connection method complying with 250.92(B)(2) thru (B)(4).
2) From a telecom perspective, I’d say this is an example of chaining ferrous components (per ANSI/BICSI N3-2020), and if the longest path is less than 3’ you’re not required to bond the components and TBC at each end of the chain. (Even though the ANSI/TIA 607 standard only refers to conduit, the intent is broader than that and should be thought of as covering various raceways. In any case, there could be a performance issue if length is ignored.)
3) Same answer as #2.
