Germany wasn't invited to the competition so the U.S. Army Air Corps won't be building a Fw-187 clone. I don't think Britain was invited either.
Nonetheless foreign designs could influence and inform other aircraft developments.Even in wartime aircraft development doesn't happen in a vacuum. How many designs were influenced by the Fw 190?
Maybe the Fw 187,an aircraft barely known outside the German aviation industry (including most of the Luftwaffe),was not so influential.I would suggest that the de Havilland Mosquito influenced the design of the Ta 154. The Ta 154 was a pretty miserable effort but that's Tank's fault.
It speaks highly of the P-38 that noone can really suggest any serious alternatives with anything approaching the required performance. I've always had a fairly neutral view of the P-38 but it may be an under rated type,at least in the ETO.
Cheers
Steve