I'm not sure about sacred soil or focalization - I don't believe we've ever used those as hard counters to cometeor and that is why I didn't mention them.

Tanks get 2 ways to mitigate all damage (increase HP and heal in the case of Thrill) between LB and defensive CD as I've mentioned. And healers can generally get an emp rain after a first cometeor breaks the sleep but before a second kills some people. Obviously, if a sleep goes out and 3 caster LBs are on the same spot and cast exactly at the same time - there is almost nothing you can do besides get the tank lb up first and pray you don't die. But three casters, even in premades who are using voip, all hitting same spot at the same time is the exception, not the rule.

You simply don't have time to countdown to cast at the same time a sleep goes out or anything like that. Sleep goes out, those LBs have to be on the floor or they will miss.