I'll just say this now: you're better off with a mini-mod over a full-mod. It has almost no new features; the basics like egg, init.cs mods, checkpoint, teleporter will happen, but beyond that, unlikely. It will have a low amount of levels (20-30), but each one is pretty good. See G3orge's Mini Mod or MBRevivded from Threefolder.
Focusing on a full-scale mod will mean levels don't get a priority until features are completed so that levels can be playable, and if the mod dies, you end up with a few levels that have no new features for, some new graphics and a few more things and that's about it.
I am not discouraging here, but just sayin' that based on our history with this, maybe you should start on a smaller scale.
(Also, Blender? That's aiming... interestingly)
(C++? engine hacks time?)
"matan, now i get what you meant a few years back when you said that "the level in mbg is beyond me" after the last rampage i noticed things were insane, and now i truly feel that too" - Dushine, 2015.