WordPress Plugin Developers?

I'm really just trying to gain some insight or figure my best course here:

I would like a "client portal area" developed for a wordpress site. I'm not claiming its an easy job (I dont know actually) and I am ready to spend some $…

It would essentially be a simple solution for me to share files with clients (they see their area after login on a client page) and vice versa (admin sees content in backend and can manage all client files there). I also want a built-in email alert for all shared files (both ways). "Nice to have" would be an option to simply post a file to my backend and it would give me to option to simply generate a link to the file, no login to access by client. This is obviously similar to countless 3rd party options but I want the content branded and accessed on my site.

I THINK I would like to have a plugin developed so I can install it on a couple sites now and possibly more down the road. I am not adept at coding and really just want a one click install with some simple settings, font/color options, and editable email/response/labeling text areas I can adjust.

What would be the best way to accomplish this?

Note: I have been previewing and testing MANY 3rd party portal type systems and they are almost all way too complex for my needs and some of them just require too many accounts and far too much budget for my solo creative company.