Hello Anthony..
There has been some discussion about HHV and whether they were using tobacco absolute in their NET's as opposed to a cold or heated macerated tobacco. I think you hit the nail on the head with your comment in regards to the hard part being getting the right "other" flavors though. Example: "Shadow" to this day remains one of the best vanilla flavors I have ever tasted.
Oddly, just before you came and checked out this thread, I brought up how Pirate's Booty came across more tea like when fresh, then evolved into sort of a spicy cigar flavor over time. A couple of folks here were saying black tea FA reminded them of tobacco.
Perhaps, and I only say this as it being a shot in the dark, finding out which flavors were available at the time HHV released their NET's may get you closer . There are a lot more flavors that have come on the market since.. I've often wondered if Shadow had a percentage of French vanilla deluxe TFA, vanilla bean ice cream TFA, and vanilla swirl TFA... I have found during my time mixing that those flavors have similar elements I tasted in Shadow.
Needless to say, it's going to be virtually impossible to get something exact. I have tried many cloned recipes since I began doing DIY and they have all (with the exception of two) fallen short of being like the original.