Which divisions will the Libs get 3 seats in? They need, at least, 3 out of 5 (is it even possible to get 4 seats from a division?) to have a majority.
It never happened since they went from 7-seaters to 5-seaters, but there is nothing preventing it, except needing roughly 60% of vote to do so.
50% or so of the first-preference vote is enough for 3/5 under STV. If Tasmania has optional preferential voting, they might even get there with less than that if transfers between their opponents aren't solid.