I believe that those aren't bogus engines. TVAL either use original engines or build reproductions.
Nope. The engines are radials; the real aircraft used Oberursel rotaries - licence built le Rhones - or captured French or British rotaries. You can clearly see the exhaust pipe below the firewall and three stationary cylinders at the lower quadrant of the cowling. If the prop is turning and the cylinders aren't, you are usually looking at a Warner Scarab engine. If there's any sign whatsoever of an exhaust pipe, it's not a rotary.
And...they sound utterly different.
TVAL's Triplanes are mostly imported incomplete US projects completed by TVAL, rather than an internal project.
(Edit: I know that TVAL have built a couple of Oberursel UR.2 replicas which may have been fitted in Triplane replicas by now - but not evident in that clip)
oldsig