Woman 1 may have to face some difficult questions from the boys conceived via her eggs. Their parents may feel, and may have expressed, their disappointment and not having a third genetically related child. Maybe not, who knows. Maybe they had another who is unrelated to the boys and that child has genealogical bewilderment. Maybe not.
They may also want to meet their genetic siblings (her children with her husband) and know more about their genetic roots in general, not just for hereditary diseases (which would be screened at a clinic) but also about mannerisms and other unavoidable genetic similarities. As this is your best friend and she receives pictures of these boys does she look like them, do they look like her? Do they look like her other children?
The message about what women can and should do with their bodies also extends to boys. If men grow up understanding the message that a woman's body is useful or can be 'used' ("used a surrogate" is often the wording in the media about couples obtaining babies this way).
So whilst the staunch feminist has a good job, career and has been able to provide for her daughter as a single mother (good on her) her altruistic actions do send a message about what women are for to her daughter, however subtle or subliminal. Had her child been a son the same would apply but the expectations are different.
I don't see the same message being sent to boys, that they should share their sperm around so men can be fathers. But I'm not on Dadsnet or other male-dominated forums so maybe that is the case and it's all about being kind and sharing for the men also.
Even if it was - and I don't think it is - a sperm isn't a baby without an egg and a vacant womb to pop an embryo into, so as a staunch feminist I'm sure your friend understands the necessary provision of women and why it aid the fertility industry in perpetuating this narrative.
And surrogacy, the use of women, is for same sex male couples and heterosexual couples (rarely same sex female couples and it's obvious why but it is possible with social surrogacy on the rise).