The Birdy of the link use another crankset than the original one that might have another chainline than the original one of the R&M Birdy. If ypou look at this link fro 50PlusCycling you will see that a road crankset has a too narrow chainline for the Birdy III (which isn't the case on the Ti Birdy that has a FSA SLK Light carbon road crankset).

You cannot put a Shimano 52-36 on the Birdy crankset because these are BCD 110 (old ones from old Shimano groupset, current one have a four arm proprietary Shimano mounting) while the Birdy has a BCD130 crankset. In BCD130, the standard double chainring sets are 53-39.

Anyway, the 36t chainring is much too short on a small wheel bike like the Birdy to use all cogs of the cassette, only the few smallest cogs are usable, so 39t is OK.

I haven't used a derailleur adapter on the Birdy, but Litepro is usually cheap, low quality parts, so I would take the Ridea.