Neither is natural. For a start, you used "members" so you need to use "they".
Our team welcomes members from all different races, be they ...
However, and it's a big however, this is a very slippery, dangerous slope to be dealing with. For a start, "black", "white" and "yellow" aren't races, they are skin colours. They are not the same thing. Using "yellow" to describe people is really not done these days. In these days of political correctness, you would be much better off using a blanket statement such as "Our team extends a warm welcome to everyone". At most, you could use "Our team welcomes members from all different backgrounds".
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