No, I'm referring to the Slave Wars, when the Emperor's Children assaulted everyone for new slaves, the events of Talon are just a single battle. The much larger campaign led to the Emperor's Children becoming just as, if not more broken than the World Eaters.
I believe he is referring to your statement of "the Sons of Horus nearly wiped out the Emperor's Children," when prior to the start of Talon of Horus it was the EC that were hunting down all the SoH in an extermination effort, so the opposite of what you said. Personally I thought it was a typo on your part.
What legions were destroyed by the Imperium? Are they the factions that were deleted from the records?
I am fine, thank you for asking. A lot's been going on, but I've been able to let it wash over me rather than submerge me. As for those of you making your suggestions, keep going. In regards to legions being destroyed or reinstated into other legions, if you were a despotic madman intent on conquering the universe, would you want there me any information getting out that there's a chink in your supposedly "invincible" legions? No one knows why, but the Emperor condemned two legions to be disbanded or eradicated, due to their primarchs, who are forever removed from history. The black library authors have commented how they'll always remain a mystery, for the sake of players being able to create their own unique back stories for their chapters/legions.
No. They were explicitly destroyed entirely. ADB denied that the Ultramarines actually did absorb the survivors of a legion, it was just Word Bearer speculation.