Hello There,
Downloading content from social media is a bit tricky, allot of projects out there but a handful work, So yeah, i can help you to create an app as well as a web centric API, it's the way to go since updating code bases of android and ios after each API, web site change will be difficult.
Lets have a dedicated server as an API for the apps which processes and generate download links and then app proceeds to download to them for the end user. Much easier way of handling.
Looking forward to hearing more from you.
Cheers!