If Maine wins, yes, they would be 1-0-0 against the WCHA, but that doesn't mean they'll automatically win the COp comparison against all WCHA teams. Minnesota, NoDak, Denver and CC have all played other teams on Maine's schedule.
Minnesota could be 3-0 against common opponents, having beaten Michigan State and with two games remaining against CC. Right now Maine is at 1-1 having split with MSU. The best Maine could do would be 2-1 if they play and defeat CC, in order to win the comparison, Maine would need CC to sweep Minnesota. If Maine were to lose to CC, Minnesota could get swept by CC and still split the comparison. If Maine loses and Minnesota splits with CC, Minnesota would win the COp comparison.
North Dakota could finish as good as 4-0 against common opponents, having beaten Merrimack twice and with two games remaining against CC. Maine could be 4-0 as well should they sweep Merrimack and play and then defeat CC. NoDak needs only to split with CC to put the pressure on Maine to win 3 of 4 against MC/CC.
A win over CC would give Maine the head to head comparison over CC and Maine could win the COp by virtue of their 2-1 record vs. Northeastern (CC split with them), unless Maine were to face NU and lose a three game first round HE series or lose to NU at the Garden should both advance that far. If that happens, they would both have .500 records against COp, and if that were the case Maine would need to win either RPI or TUC to win the pairing.
Denver is currently 2-1-1 against COps (Split with UVM, and win and tie against CC) with two games remaining against CC, and one against BC (potential to be 5-1-1). Maine is currently 1-1-1 against BC and UVM with at least three games remaining plus any potential playoff match-ups. If DU goes 4-2-1, Maine would have to win all three remaining games against BC and UVM, and then not lose to either in the first round to win the comparison. If they go 4-1-1 and then lose to either at the Garden, they would halve the comparison and it would come down to RPI and TUC to win the pairing.