I would recommend starting with a premade mod pack and a YouTube series that's currently using it. Direwolf20 authors his own packs and creates videos using those packs. The twitch client allows you to install various modpacks for Minecraft, including Direwolf20's
In short, Windows 10 Edition has not replaced the Java Edition, and IMO the Java version on PC remains the best way to play, especially if modding or server communities are desired.
The Windows 10 one (which as here announced just got scripting beta), the XBox one and Android/iOS versions are all based on the same code base and labeled "Bedrock Edition". There's a bunch of other variants for other consoles etc, but less relevant. The Raspberry Pi one also had a (I think Python?) scripting interface, not sure if they still maintain it.
The Raspberry Pi has a minimalist rendition of Minecraft that let's you script it with Python. Just downloading (or getting n00bs) the official Rapsberry Pi distro Raspbian includes Minecraft with it.
However, (this may not be true any more, but I think it is) you get a free version of the win10 store version of minecraft with a java edition purchase. So just buy the java version, and you get both (and the prices are pretty close last I checked)
Look into Minecraft Forge.
Not sure how relevant all of this is now but we got it up and running on an older iMac pretty easily.