Hi Amber,
You can create destinations in order to consume odata services inside an html5 application and that way you don't need a reverse proxy. If you use webide to develop an application, you can consume the web services that are defined as destinations at the hana cloud platform cockpit. And you won't need reverse proxy.
However I'm not sure what is the issue you're facing exactly and I'm being honest, I've never needed to build applications on HCP with a team of developers. You could use webide defining destinations and keep the benefits of application management features and git. For production you'll need to buy licenses. Or you can use whatever java platform you like, and whatever git tools/platforms you like externally. And then when you're done, deploy your app in one place. By the way, you can build your project and then upload the war file using the cockpit (Java App.-> Deploy ). In this scenario, there is no need to use eclipse. Whenever you've got to upload an older version, get the appropriate version at your code base, build it, upload it. You might also want to check Jenkins for continuous integration Meet Jenkins - Jenkins - Jenkins Wiki.
Cheers,
Huseyin.