Is it possible for America to ever adopt Confucianism/Taoism?
America doesn't adopt religions. Individuals may convert. One day, the majority of individuals may convert to Confucianism/Taoism. I doubt it, though.
I strongly doubt it, we are a country built on Christian principles
America is the most religious and most Christian of any First World/Developed country. On our currency, in our pledge of allegiance, and at the begining of a session in Congress or the House, we put our trust in a (Christian) God. All of our Presidents have been Catholic or another section of Christianity.
I'm Buddhist and I'm going to say: very unlikely
Many people in America follow such.
I follow many Taoist principals
have for almost 30 years.