I'll go ahead and put in the "No, certainly not" reasoning. Someone has to, right?!
- Thanksgiving is (by far) the biggest travel day in the USA.
Most worker-level employees would find it annoying (if not frankly bizarre) to have a work-event scheduled in the Thanksgiving "season".
In the bulk of the country it is a family oriented weekend. Even in the few very progressive parts of the country, it would still be a strange time to schedule some sort of work event, as, it is the "time everyone schedules some sort of party".
- ... and they would indeed just think of it as a "work event". You're one of the "bosses". You know how people think about "bosses". That's you. (Sad but true right?!)
What you think of as a cheery invitation, helping out the lower classes as it were, being a modern equitable friend to everyone - they are just rolling their eyes and saying Mr. Smith wants us over at his house, what next. (!)
Based on your description of this happening party (I want an invite!), I get a particular vibe of how the party is going to be. You're a social group and know how to throw a party. My "party nose" tells me this is just not the type of party you invite "some juniors from work" to; they'll just feel out of it.
(On a roll now!) You explain these are not "your" staff. They're someone else's. (You have them on projects occasionally.) To me that I'm afraid just seems wrong. Their bosses will be p'd off that you're oddly inviting their guys around to your swinging joint. Why would you do this? For what reason?
Officers wanting to fraternize with enlisted ... is it ever a good idea? They bluntly just don't like you. You're the boss, or a boss. All they want you to do is keep the coming rolling in money, so they can collect a paycheck, and go home to the bar/family of their choice.
On top of all that, they will feel obligated to say yes. What do you think when someone from the board casually asks you to come to their Hamptons house on the Saturday? Same.
As user70848 points out, there's the bizarre aspect of inviting a handpicked few, and also not your boss. It's .. not coherent, you know?
For me it's a No!