All those bikes are much bigger folded than the Brompton. The Vello and Ahooga do not have a folding fork (only the Vellobike+ has a folding fork, not the Vellobike).
I also saw pictures of a 20" Brompton clone with a titanium frame but I do not know where the frame comes from and if it is available.
20" ETRTO 406 Brompton clone
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Note that a 20" Brompton must be bigger folded than the original ETRTO 349 Brompton because the rear wheel folds under the main frame tube and to manage place for a 20" ETRTO 406 wheel, the frame and rear triangle must be enlarged. The fork must of course also be enlarged.
Also the front and rear OLD of the Brompton are smaller than the standard 100mm/135mm of your wheels.
The Birdy is compatible with ETRTO 406 wheels.because its rear wheel folds besides the main frame tube, not under that tube and because it is designed to accept 50mm wide tires on its ETRTO 355 wheels giving a total diameter of about 455mm, so ETRTO 406 wheels with 28mm or 30mm tires (total diameter of about 462mm or 466mm) fit on the Birdy (and Pacific Cycles now sell the Birdy R20 11SP factory equipped with ETRTO 406 wheels and Panaracer Minits Lite PT tires).
The folded Birdy is only slightly bigger than the Brompton and much smaller than the Tyrell with ETRTO 406 wheels.