Dude, use the search function.

Just kidding, I think you'll find someone in this club that can answer your question with first hand knowledge. Unfortunately it's not me.
I have heard some folks in the club, whose opinions I highly respect, claim that the 1960 TBird and the new Epiphone Thunderbird Vintage Pro sound relatively similar. And that the 1970 TBird sounds a bit brighter than the 1960 TBird. So if you can find somebody that has tried both the Embassy Pro and the TBird Vintage Pro you might be able to triangulate an answer to your question. IIRC the Embassy Pro has the same electronics as the Vintage Pro. If that's correct, and if the wood selections are similar along with the neck/body construction I'd expect the two to sound very close to each other and by extension not far from the tone of the 1960 Gibson Thunderbird.

I'll take exception with your use of the word "inferior" especially as implied to the entire Epiphone line up.
Gibson has structured the Epiphone offerings to appeal to players looking for Gibson like products at a lower price point. Do not confuse lower cost with "inferior". My $2000 Gibson 50th Anniversary Thunderbird falls short of my $600 Epiphone Thunderbird Vintage Pro in the build quality, fit and finish category. Tone wise and playability they are pretty much neck and neck. I certainly would not consider one to be inferior to the other. The Gibby has better tuners, and the Eppi a better bridge, the Gibby better finish, the Eppi better pickups. Bottom line, the Gibby TBird is a bit over priced for what you get and the Eppi VP is way under priced for what you get.
I have a Goth Bird also, and at $300 it's worth every cent, maybe more. One could argue that having a bolt on neck makes it inferior to the neck through Gibby bird design, but that logic would get you burned alive on any Fender forum.
Some folks are drawn to bolt on necks, some prefer neck through designs and others want set necks. Some people want the deep dark tone of a Goth over the more articulate tone of a VP. Some people want the easier reach of a Short Scale bird over a full length one. Some people like the durability of poly finishes vs nitro.
In other words it just doesn't make sense use a broad brush to paint Epiphone products as "inferior" to Gibson products when superiority and inferiority are terms largely defined by individual users. Are they less expensive, yes. Are they inferior, not necessarily, depends on what you want out of the instrument.
I've steered clear of Behringer products for as long as I've been playing bass. Not from any first hand experience but from all the quality control and equipment failure issues I've heard on Talkbass. Right or wrong, that's what I've done.
Interestingly, that's exactly what I did for most of my bass playing life with Gibson products. Heard horror stories - massive neck dive, self detaching headstocks, mud or thud tone, embarrassing fit and finish, an unusable three point bridge, a jerk for a CEO, etc. With the exception of the last item none of those issues has turned out to be true to me (and the jerk is now gone so even that item is a bust now days).
I wonder how well founded my Behringer phobia really is. I'll probably never find out at this point because I've got all my rig needs addressed for life.
I just assumed it was a vintage exercise tool for your index finger.
Duke - loved the Cobalt flats on my Eppi VP Bird. Took them off after a couple of weeks to continue down the string experiment path with the VP in hopes of finding the perfect string for a very unique bird.
On a club members recommendation I tried Fender 7150ML Strings and think I've found something I like even better than the Cobalt flats on this Bird. They've been on for a couple of months now and are wearing very well. Because they are a round string they have a bit more top end definition than the Cobalts flats and with the pure nickel construction they have a bit more bottom as well, maybe just a tad less mids but not nearly shy enough to get lost in a mix. They're cheap and easy to get, try some out, I'll bet you'll love em.