Re: syncing audio to video and subclipping

personally I would suggest instead of re-encoding the files :
Drag all the clips to an new empty sequence timeline and synchronize the video and audio. once the all the pairs are ready, link the video and audio in each of them and rename the clip as if you would have done with a subclip.
from now on, this sequence is dedicate only to these clips, to use as sources. Think of this sequence as a sort of bin.

Now you can open your main edit timeline. rearrange your workspace so you have two timeline windows open simultaniously, and position your "synchronized sources bin" timeline above your "main edit" timeline.
Now if you want to import a clip into your main edit, you can just drag and drop a clip from one timeline window to another.
You can also open the clips in the source window by double clicking on them, just as you would any other regular clip, and use clip markers and in and out points to insert or overlay them into your main edit sequence.

Sorry for the long-winded explanation, it's actually quite a simple process once you get the hang of it, and while not as clean and simple as subclips, it's still worth avoiding needless re-encoding IMO.

Cheers, Jon