Well I literary wrote down what I sucked out of my thumb at that moment so refinement is always needed haha

If you make it in HTML5 and JS, they should work on all devices

Even the older versions

If you could make it in that way, no lite-version should be required

The reason why I pointed the lite-version as a version without ads is because what ever the coding is, the ads are always the ones slowing everything down

Soon there will be the need for online-meetings I suppose x'D
That depends if you use ads optimized for mobile phones or not, if not they will slow down the browser obviously, as they can be more demanding.
Sites overloaded with ads are a good example of an instant-slow-down due to required rendering via CPU, RAM or both.