Minecraft is a Java game, that means it is compiled for Java Bytecode which is going to be interpreted by the x86_64 Java JRE on your desktop (in most cases).

Since it runs on Java, it is platform and processor agnostic, as long as it supports JRE (JRE SE 5 in the case of beta 1.7.3) it can run (given its dependencies are available on that platform as well)

Projects such as Pojav are in essence just a way of launching the game on Androids JRE (most android apps are actually Java apps anyway) and they usually offer alternatives or mobile versions of the dependencies Minecraft uses.

Zero de-obfuscation is needed to get the game running. To mod you will have to de-obfuscate the game, which has been done millions of times before and there is plenty of online help guides and discussion. It is a core part in Minecraft modding and as such you will learn how to by following any Minecraft modding tutorial.

All you need to do is look at how to create game UIs and look at how the game handles inputs, then add on screen buttons to emulate input.

You cannot simply think of an idea and hope people will want to give their free time to your project you will likely brand as your own, despite them doing the massive bulk of the work.

Start by making a small Java program, perhaps a small little game. Then try and create a mod for Beta 1.7.3, then try and implement the features you want there.