Complex CRM for a wide range of audiences (with different data needs)

I'm not really sure where to start with this request but I appreciate anyone's input and willingness to help. Essentially my self-funded unit inside a higher education institution needs to swiftly upgrade its Access/Excel-based client & audience information to a well-rounded CRM system.

Coming from other institutions before taking this job, I immediately saw how archaic our Excel-based processes were. I have experience with Salesforce and Ellucian Recruit CRM from other jobs as a user (not admin/developer). Now, to get my unit into the 21st century, I am researching how to best go about choosing and setting up a CRM solution that addresses some complex needs.

1. We have a lot of different audiences. From individuals who would be fed into a CRM via an application, prospective clients, "people we meet on the road", partner organizations (voluntary), volunteers, on-campus partners, participants in a variety of programs, etc. For most of these we need to track when we engaged them, when they were part of our programs, and for some we would track our sales.
2. Integration with Mailchimp, Quickbooks, potentially even things like WeChat
3. Document storage/upload support, as well as email tracking with Outlook.

My questions for this community are as follows:

• Is there a CRM that immediately jumps to mind based on these requirements? Is Salesforce affordable for 10 users, knowing that we'd like special integrations and many customized audience profiles?

• Is there software available where I can "map out" my needs? I would love to gain insight about how people go about the ideation stage of CRM development to demonstrate to higher-ups why and how a CRM would be beneficial. I'm thinking flowcharts, data field requirements, etc.

It's a daunting project for sure. Thanks for any feedback!