I don't think "Fembot Fashion" would look like any one thing, and certainly no one can predict what fashion is going to look like next season much less next decade. But I think we could probably make some inferences about what the industry of fembot clothing might look like.
Assuming we're talking about non-emancipated androids that are owned... Fembots are going to dress however their owners decide to dress them. People/companies would own fembots/gynoids for all sorts of reasons. Even if we're just talking about retail fembot owners who want their companions to dress sexy, that's going to look like something different for everyone. Some owners might want their fembots to walk around completely nude or in lingerie. Others might prefer tights, skirts, and turtlenecks. One thing is for sure: I think there's going to be a lot of demand for fembot clothing that fits the male gaze.
How often have you wanted your girlfriend to wear that one sweater or that particular pair of panties that you like? If you actually gave men control over the way their partner's dressed, and their partner's were game for anything you'd probably see some pretty out there stuff. If a guy's thing is lacy bras he going to buy lacy bras in ten different colors for his fembot. If he likes fishnets, or leather, or stripper boots he's going to keep buying until watching his doll try on those clothes stops giving him dopamine. I mean, just think about how thirsty men are for cos-players. Your wife won't dress up as Cammy from Street Fighter, but your robot will do it without hesitation. Picture tax here:
https://cdn.worldcosplay.net/628290/bff ... re-740.jpg Cosplay kits for fembots would, by itself, become a billion dollar industry overnight. The advent of Fembots would allow textile manufacturers to mass market women's clothing to men and directly cash in on the human sex drive in way very few products actually can.
And I think what you might start to see is that Fembot manufacturers would probably offer premier OEM clothing. Clothing with functional openings for access ports or maintenance surfaces. Clothing that is specifically tailored to the factory measurements of your robot. This industry would be an absolute goldrush with the winners being whoever could figure out how to best manufacture semi-bespoke and tailored clothing quickly and cheaply.