Extent of map file adding

can you make new blp, mdx and put it into the mab and be able to use them by editing path strings in we?

What do you mean? You can make the unit a custom model, change the name of it, and just select the path of the unit. It must be put into the map, though. Is this what you mean by paths?

Of Course you can!

Just import them in the right fields.
like Units\Human\etc.