Where's the proof this is a 1929 poster? It looks like a 1960s re-release. Was it common to include foreign languages on posters back then?
Well frankly I don't have to prove to you anything, and you can think whatever you want about it.
Yes, it was quite common to include foreign languages on posters back then (and in the 30s, 40s, 50s, etc)
Look at the altered-Maria image in the poster - the same as from the yellow/green advertisement Erik posted.
Look at the unique lettering for メトロポ (Metoropo) on the poster and advertisement (and the program book a couple of photos down on the Metropolis page) and see how it uses dots instead of strokes on the Me, To, and Po katakana.
Plus look at the bid history. While the winner was a deputy service, the underbidder (Pollymagoo) is one of the most famous long-time collectors in Japan, and the 3rd, 4th, and 6th place bidders are all quite well known also (I would say think Borst, Allen, Caiden, Shimkin, Nemith-type collectors but some of those names might be lost on you).
As soon as I saw it listed last week I contacted a couple of long-time collectors friends in Japan (you would probably call them elite) and they both confirmed it as original. That was good enough for me.
As to the Ghoul poster, it has always been my understanding that it is from 1935. Towa-Shoji certainly distributed films (in fact they distributed the very first film made from Toho in 1932), and the writing of their name from right-left next to the logo is definitely a pre-war practice. The odd size of the Ghoul poster is also another indicator that the poster is pre-war.