"if #4 THNN is used, does that mean it will meet the requirement??"
12 conductors (current carrying) of (I am assuming) ThhN to panels with load diversity. (i.e. un-equal loads on each phase.) 95A @ 50%=47.5A
If you call the neutrals non-current carrying 95A @ 70% = 66.5A (see 220.22) We don't know what the loads are do we? (See Annex D for examples)
This is not including calculations for ambient temp. (A boiler room was mentioned.) Or 110.14(C)(1) provided an Inspector carries a calculator.
Or if the AHJ allows feeders or branches of seperate metering in the same conduit or enclosure.
As I dont think is 310.15(B)(6) is applicable with all in one 2" conduit.
Commentary:If a single set of 3-wire, single-phase, service-entrance conductors in raceway or cable supplies a one-family, two-family, or multifamily dwelling, the reduced conductor size permitted by 310.15(B)(6) is applicable to the service-entrance conductors, service-lateral conductors, or any feeder conductors that supply the main power feeder to a dwelling unit.
I know commentary is not code, but I don't see 310.15(B)(6) as an exception.
Why not 4 cables or conduits? Then #4 is fine... You could do 100A!