Welcome
If I understand you correctly you have brake fluid leaking at the front and back of tunnel

If that is the case, yes the MC leaking will go into the tunnel and leak out at either end

Have you pulled any drums to look at the wheel cylinders?
What I would do iffin it were mine is replace MC,WC, flex hoses and shoes.
If you can do this yourself it is not that costly and is worth it for the piece of mind. Just a little FYI the rear axle nut is torqued to about 250#

and needs to that much or you will strip out the splines in the drum if less.
But you can just put in the MC for now and bleed them but usually other leaks will show up.