1056 can slow down , but it will attenuate to 75% if its healthy, Did you mae a vial into a starter, what size starter was it??
1056 can handle a little higher temps no worries so maybe you can raise the temp to 20-21 deg to give it a boost, As Linz says racking will do 1 of 2 things, but the fact that 1056 is a low flocc yeast you will still have a bit in the wort...
Has the yeast head droped yet?, I have found that 1056 will keep a nice head of yeast on the top of the beer untill its done, then it will drop off, I would say that if is god a yead of yeast its still working.
Forget what your air lick is doing, they are a barrier for bacteria and nothing more, too many homebrewers rely and what the airlock is doing and panic if there is little or no action, when using ale yeasts in particular, the top of the brew and a hydromiter/refractomiter are the tools you should be using to see if the beer is fermenting;.....oh thats rambling on again....not much help
If it were me, ill raise the temp for a few days and see what happens, when you take your test readings, have a loo at the temp of the sample as well, with the weather we are having right now the sample can raise a few deg in minutes