Good luck with this. Some help from my part: There are several Belgian vehicles in the Dutch Trainset and the 2cc TrainsInNML set, so you could look at that for stats (and possibly sprites if you follow their licenses).
One question from me, why not host this on the OpenTTDCoop Devzone? Then you have version control, the webtranslator that people can use to translate this set, and automatic builds.
1) I may be Canadian but I'm not well versed with French and I dont know any Dutch. Thus everything will be in English
until I have a translater to make French and Dutch language files for the set.
See my previous comment on the Devzone.
2) I'm still very green with coding so I can't do any fancy features or things I really want to do, like having the ability to toggle the selectrion for liveries (I would like to be able to have a Parameter for : Real Liveries, 2cc Liveries, and a Refit option so players can have both)
You would need a parameter, and several switches. 1 for the cargo_subtype_text (as that will be shared between all vehicles), and some switch-chains to end up at the correct livery (depending on parameter value and if possible, selected cargo_subtype).
3) I still dont know how to make the Electric MU cars/trailers appear with powered sprites only when players put in a powered wagon. I want it so that when you place a unpowered MU Wagon in, it doesnt show a pantograph or any electrical gear on top. Powered MU Wagons should only have the Pantographs and roof mounted gear.
If you implement them the same way as they are in the 2cc TrainsInNML, each vehicle to which they may be attached would have 2 livery override blocks, one for the unpowered wagon and one for the powered wagon. In the block of the unpowered wagon, you point to the spritesets without a pantograph, in the block for the powered wagon, you point to the spritesets with pantographs.
Coder of the Dutch Trackset
| Development support for the Dutch Trainset
| Coder of the 2cc TrainsInNML