I don't plaster soaking wet walls.... And especially not at these temperatures.. So you should be much more concerned about the temperatures and especially frost. I seem to remember that the datasheets mention temperatures of ...not below 5.00 degrees... and that above all the brick must not get frost from the outside.... So check, have it shown or postpone. The plaster is the last layer you will see in the house for many years.... I wouldn't rush that. You will regret any cracks forever.