majority of salamences are now mixmences+1 eq on rhyperior:103.77% - 122.10%
always outsped and ohkoed
+1 outrage on swampert:94.51% - 111.22%
not the best counter as pert will have taken some damage during its time as a lead.
now cress is a good counter, but it will have trouble switching in on anything thats not eq, as +1 outrage does62.16% - 73.20% on a 252/252 bold cresselia.
cress hits for 80.12% - 94.28% with ice beam, so salamence has already killed two pokemon before cresselia can switch in and ko for sure.
Cress is probobly the best mence counter-scarfgar with hp ice, but its not a good counter by far.
so let's look at them, with the standard new mixmence's ev's these are the following outcomes on cresselia:
Draco Meteor: 341 Atk vs 296 Def & 444 HP (140 Base Power): 226 - 267 (50.90% - 60.14%)
Outrage: 327 Atk vs 372 Def & 444 HP (120 Base Power): 148 - 175 (33.33% - 39.41%)
Even with those two attacks, cresselia is not even 2HKO'd
Now, let's look at DDMence (offensive variant) against Cress. It's is true if DDMence had one DD then those number are correct. But first of all, with cress out, it would also be extremely hard for mence to really do anything. In fact, Cresselia's ice beam would actually OHKO the standard DDMence as the standard DDMence usually goes for naive or naughty, and both lower the Sp.Def. Even a neutral natured no sp.ATK EV invested Cress (the standard) will OHKO the standard DDMence with the help of SR as shown:
186 Atk vs 176 Def & 331 HP (95 Base Power): 292 - 344 (88.22% - 103.93%)