Can I create a Provider Hosted App that will work in both SharePoint Online and SharePoint on premises

Hello,

We are planning to create a provider hosted app, we have following questions pertaining to the development,

1. Can we create provider hosted app that will work in both SharePoint online as well as in SharePoint on premise ?
2. If we are using low - trust apps is it mandatory to have Azure subscription (for ACS) ? Are there any alternative for ACS that we can use for SharePoint on premise ?
3. Can app be developed as multi tenant i.e. single app for multiple customers ?
4. Is it possible to develop single provider hosted app that supports SharePoint Online - with low trustand SharePoint On premise with High Trust ? I checked this link, will this be useful?

Any input is highly appreciated.

Thanks,

Hatim