Just look at OTL's Harry Hopkins.
You obviously know nothing about Hopkins and his relationship with FDR if you think Anne Colleton could have had the same relationship with Featherston.
Hopkins had been in public service since the 1920s. He first came to Governor FDR's notice for his work in that state's emergency relief organization. His work was so good that Governor FDR promoted him and, after the '32 election, President FDR brought him to Washington to run the national version of NY's relief program, the WPA.
Hopkins was part of FDR's inner circle, one of the designers of the New Deal, and held a series of appointed positions within FDR's administrations. FDR was even grooming Hopkins for a presidential run in 1940 when Hopkins' bout with cancer scuttled those plans.
All Colleton ever did was write checks and twist arms behind the scenes. She was not part of Featherston's inner circle, she had no input on policy, she never implemented policy, and she held no positions. Suggesting she had or could have had anything resembling Hopkins' career or impact is ludicrous.
He wasn't the Secretary of State or an official ambassador, but FDR still used him as his primary envoy to Churchill in 1940 and Stalin in 1941.
Good sweet Christ...
It's as if you believe FDR just picked Hopkins out the phone book.
Hopkins was sent to Britain in '40 because FDR couldn't get a straight story out of the official ambassador, Joseph Kennedy Sr. The UK government was also so pissed with old Joe that they requested FDR send someone he trusted to ascertain what the real situation was. Thanks to his bout with cancer, Hopkins was no longer running the WPA and was at loose ends. FDR trusted him implicitly and, thanks to Hopkins' 10+ in federal service and closeness with FDR, knew that Hopkins could be trusted to report back impartially.
Hopkins was then sent to Stalin in '41 because at that time Hopkins was the
administrator of the Lend Lease program. FDR wanted to know whether the USSR should be included in the Lend Lease program and what sort of materials would be needed, so he sent the man who ran the program in question. Shocking, isn't it?
Anne's not going to be made Secretary of State, but she could certainly have served in a Harry Hopkins like role.
No she cannot because she has nothing resembling the skills, experience, and reputation Hopkins did. More importantly, Anne does not have the same relationship with Featherston that Hopkins had with FDR, a relationship that included a long shared history making and implementing policy at the national level.