What we believe to be my half-uncle (16% shared DNA | 1,118 cM), has a believed half-sister (1,660cM). My relation to the 'half-sister' is (8% shared DNA | 541 cM) which would most likely make her my 1st cousin 1x removed. They are both about 30 years older than me. My father was adopted (died in 2012), and we believe they all share the same father making me a half-niece.
Is this possible with having so little cM/DNA with the woman?