"Q: It’s not specifically stated that anything other than Veterans can take a Dedicated Transport. The assumption is that all Kill Team combinations,Terminator units, etc. can take a Dedicated Transport within the limitations dictated by the types of model in the squad. Is this correct?
A: No, but you can select Transports as Fast Attack
options, for example, if you like."
So no, you can't take transports for Kill Teams.
I don't think you're parsing the question right here. I'm reading it as:"Q: It’s not specifically stated that anything other than Veterans can take a Dedicated Transport. The assumption is that Terminator units can take a Dedicated Transport within the limitations dictated by the types of model in the squad. Is this correct?
A: No, but you can select Transports as Fast Attack options, for example, if you like."
The question here is asking if Terminators, who don't otherwise have a Dedicated Transport entry, can take a Dedicated Transport. They can't.
All Kill Teams, on the other hand, MUST include a Veteran squad, which gets access to a Dedicated Transport as part of its unit entry, therefore the Kill Team which they then become a part of has that Transport (subject to the other limitations that the FAQ brings up).
I can *sort of* see your point with the Boltgun/Shotgun, but if that's the case, why is Boltgun/Special Weapon and Combi-Weapon/Shotgun still legal?
Because it's clear that GW doesn't understand the intent behind the question. The question was asked with the intent being, "We've found this loophole that, amongst other things, allows you to take a Bolter and a Shotgun. Are all versions of this loophole intended?" and the question answered was, "Can you take a Bolter and a Shotgun?"
I feel that it's clear that this is a loophole that was clearly unintended, yet exists due to the way the Codex is written. The fact that GW have ruled that Bolter/Shotgun isn't allowed implies that Bolter/anything else isn't allowed either, but I'm sure there will be rules lawyers out there who will argue the toss.
As for the Beacon Angelis, I also wouldn't mind, except that it uses the same wording as the Icon of Chaos, and the Icon of Chaos is actually allowed to work on the turn that it arrives.
Games Workshop have never been consistent with how things work between different Codexes. Back in 4th Edition it was possible to have three different Storm Shields on the tabletop that each had a different ruleset: the 4th Edition Dark Angels Storm Shield rules were different from the 4th Edition Space Marine Storm Shield, and both were different from the 3rd Edition Daemonhunters Storm Shield (that carried over into 4th Edition).
A Codex is designed as a single entity with a particular mindset in mind. GW has proven over the past 21 years that they will not errata things to match other Codexes for the sake of having a unified ruleset, rather preferring that each individual Codex is as close to the initial intended mindset instead.