Trying to match up your needs with available cloud apps is a common challenge, especially if you have hardened requirements that may be very unique or tailored to your organization. In that case, barring a 1:1 fit around each discrete app, you'd want to include configuration flexibility (to include solid APIs and/or integration add-ons) in your assessment of potential tools.

You'll definitely need to go through the grunt work of establishing a set of selection criteria and evaluate your potential solutions against that criteria, as well as factoring in the tradeoffs associated with loosening "requirements".

This can be a pretty complex exercise, so you may need outside assistance. But, I'd start by determining what your true critical requirements are and examining whether you can find any 1:1 fits for requirement categories. It sounds like flexibility in app configuration and the ability to develop modular extensions to the app would be important selection criteria (in order to accommodate tailoring options). For capabilities where you find no (or a very weak) fit, you'd want to be able to integrate with apps that you build on a solid, compatible platform-as-a-service offering.