Mobility of your solution, 0 ? ;D
Set yourself by the line of VP, wait for attack, force retreat, move in grens to decap, place MGs little further, don't be greedy, don't advance too much, get back to MG line, have 251 behind and pios nearby for reinforcement and MG repairs.
You don't need to worry about the map control(and therefore mobility) that much, because its 2v2 and you have OKW partner for a reason there.
I don't use mortar or mines, but mines actually sounds good for flank protection.
You don't need LMGs with this setup, because you are suppose to outlast, not outdps opponents and suppressed cons can't fight back.
What he said is reasonable and similar to what I use.
2 HMGs, pios and 251 is the key here.