do I need a disconnect between the MNPV and the Classic 150?
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Yes, you need a disconnect that is near and within site of the Classic on both the PV side and the battery side. On the battery side, over-current protection is required as well. On the PV side a switch is technically sufficient. In some cases the MNPV could be the disconnect, but usually it will be too far away.
not that there's any such thing as overkill when it comes to trying to protect your investment from surges and such, but you do have my curiosity why you have 3 at the mnpv? i would think maybe 2 there at the mnpv and one just before the classic. putting one at the classic would help minimize the possibility that the pv wires could still pass something through to the classic.
Niel, that is 1 per array. Just working on the overall layout for connections. will have to add an SPD for the inverter, on another page, and the CC I imagine. you mention 2 at the MNPV , how/where did you envision them connected?
i'm going by your diagram which you show 3 spds at the mnpv. i don't have an mnpv or looked at the pic of it, but you shouldn't need one for each string unless there is a long distance between the strings and the mnpv and in that case the spd would go to each pv string's location rather than at the mnpv. even putting one at each pv string wouldn't be all that necessary in my opinion as 1 at the mnpv and one at the classic's pv input would probably suffice quite well. shorter pv runs need only have an spd at the classic's pv input.
now maybe i drew a wrong conclusion based on your diagram, but it did spike my curiosity.