Sorry if I am confused here, but the BMS and the dual 2AWG wires are all on the negative side right? From the main neg battery post to BMS to negative bus bar - and no fuses are needed.
The T-class fuse is best close to the main positive battery terminal then leading to the positive bus bar. There is no clear advantage in my mind to using a pair of 2AWG wires vs a single 2/0 wire (which has the same total cross sectional area) on the positive side.
Am I missing something? I don't see the reason the pair of BMS terminals should affect the wire choice to the fuse.
Of note: ABYC states that using pairs of parallel wires is acceptable to lower the voltage drop (not a big deal here with short wires) but that each individual wire should be able to handle the whole load. So that's one vote for a single wire, but may be less critical when not on a boat.