I suggest reading the entire non C part of the reference manual after you have a basic grasp of lua, not to know it by heart but to know what concepts are already available, otherwise you’ll constantly be reinventing the wheel. Afterwards you should read the files in c:\Program Files\Renoise 3.0.1\Resources\Scripts\Documentation\ (assuming you’re on windows). The most important after the introduction is song.lua.
But all in all I suggest you go onto the renoise IRC and ask any questions there.
-VST browser for folders rather than authors
The contents of renoise gui elements can not be accessed directly (this is written in introduction.txt I believe), most parameters can though.
-Auto MIDI mapping like Ableton
I’ve edited the script danoise suggested a little to no longer require actual searching of the parameter name
Can’t quite remember what was in ableton, but it’s not possible to automatically bind any non-not-song-independent as you do with ctr-m.
-Save and recall Grouped tracks
Possible, but considered the complexity, you might just as well learn/set the keybind for saving an effects chain and load what you need from the disk browser via drag and drop or otherwise. There’s a tool calledxrni merger, you might look at that.
If I understood correctly, use a hydra
-Time measuring tool that automates default pattern length, highlighted areas, LPB, and can change through out the song.
You can not edit those parameters, except LPB, also changing anything via scripting in close to real-time is not guaranteed, you can achieve pseudo realtime if you’re repeating code is efficient enough, Illformed made a efficiency benchmarking tool for lua scripts some time ago.
May I once again recommend coming to the IRC, you’d get answers for small questionsmuch quicker.