Hello
I have over 28 years extensive experience with Filemaker Pro and have developed, deployed and maintained many instances from very large and complex down through to small more simple deployments.
The project details/description you provided, is doable, if you would like to contact me and send through some additional details on the finer points of data that you are looking to store, view, run reports on etc., for your clients and vendors, as well as any design ideas (colours, processes, sections, etc.), I can review the details and get back to you again with a more details proposal and some milestones we can work through together, in order to complete the project for you.
Thank you
Darren