Hi. I’m not the best at sexing silkies either, but I am 100%sure that the one in the first picture is a roo as I can clearly see streamers and the one in the third picture is a hen.
The strange thing is that their brother (he is 23 weeks old now) started crowing one month ago. My friend, his owner, recorded him when he first started crowing.
I won’t be able to keep them if you are right. Cockerels are not permitted in the area were I live. They both have lovely temperaments. Very sweet birds...