Hello, what a great project! I already can see ways that I can contribute in a significant way. My background is in Communications, Public Relations and Branding. I also do graphic design and have a lot of experience in marketing. In addition, I have approximately ten years of experience connecting multiple platforms, especially in e-commerce. I am also a Native English Speaker, which is the fundamental baseline in connecting and doing the tasks for each platform correctly and its code. We can get this done in several ways, but in my experience, going over each platform and ensuring everything is filled out and functioning correctly before the connection happens is vital. Furthermore, Facebook/Instagram, as of late, has been more and more restrictive on every detail associated with each account.
The time depends on how you currently have everything set up, how many products you have etc. I cannot control those platforms' approval processes (if any), but I can certainly accurately do everything to complete the end goal. It should only take a few hours, but it depends on various details of your content.
Although I have no reviews on Freelancer, I can assure you that my experience goes beyond here.