thanks for your interest in ALK2!
Unfortunately, Logic plugins can by design only be used inside Logic and I'm quite sure this won't change in the future.
What you can always do is simply to record the audio beforehand in Logic, bounce it as an audio file and import it into ALK. However this takes away the possibility of playing these sounds in ALK.
There are ways of routing internal audio in OS X (you can take a look at Soundflower or Loopback), however the latency when recording might be high...
If you have an audio interface with more than one stereo input and output channel, you could physically route Logic's output to an input that would be recorded by ALK. However the latency here is questionable, also because of the fact, that you would in any case have to run ALK2 and Logic alongside (which might incur a high CPU load).
The best solution (if you want to actually play Logic's sounds, not to prerecord them) might be to find a high quality VST synth or Sample library that produces the same sounds as Logic's inbuilt plugins. There are tons of great free audio plugins alongside industry standards, like Native Instruments' plugins, u-He, etc.