Bonjour Olivier,
I can help you with your project probably.
I don't take freelance projects for the last time, just was looking if there is something interesting in 'AWS' tag, and saw your project. Looks like you have a leak of applicants, so I could make a try.
I should say ahead, I don't have Salesforce experience. I'm mostly work with various AWS services and PHP/JS stuff.
Thanks, Alex