Quicker way to go through 550 variables with very similar code
This is an odd code review for me. I could talk about giving your variables meaningful names, proper indentation, avoiding activate and select, extracting functions/subs, looping over ranges using a For Each, etc. , but I'm not going to talk about any of that. Because you don't need code to do this at all.

With some patience, you should be able to craft a native excel formula that does all of this. It will be less readable than code, but it will also be exponentially faster. 

Let's start here: 


wsMaster.Cells(i, 3) = Application.VLookup(wsMaster.Cells(i, 1), Vrange, mf_pLN, 0)



and translate this into a formula.

=VLOOKUP("[MasterTab]!$A2","[Sheet2]!A:ZA",mf_Pln,FALSE)


We obviously can't use a variable there, so let's take a look at how we get that value. 


mf_pLN = Application.Match(mf_pLN_TEXT, Mrange, 0)



Okay, so let's nest that into our function. 

 =VLOOKUP("[MasterTab]!$A2","[Sheet2]!A:ZA",Match(A$1, "[Sheet2]!$A$2:$ZA$2", 0),FALSE)


Take careful note of the dollar signs. They make the reference absolute, so the reference cell doesn't change as the formula gets copied into new cells. Those without a $ are relative and will "move with" the cells. 

Now, just nest this inside of your COUNTIF and you have a formula ready to go into your worksheet. Fill right, then down. 

Of course, this works on a single specified worksheet. You'll still need to loop through all of the worksheets to actually build your final formula. Replacing the target sheet name accordingly. 

It's going to be nested deep, but a considerably faster solution using formulas versus VBA.