For the Lurker and one_winged_angel. Quick flashes of dreams are ether HI, which can also have other types of HH such as auditory i.e. sound, or they might be the start of dreams that end abruptly when you focus on them too much. Ether way, they are a sign that you are very close with WILD.
For frekinrican. The old hag is not very common. It is related a bit with WILD because you remain aware as you go through the transition from awake to sleep when doing WILD. The old hag was well known long before WILD was. Most people who have the old hag, do it when waking up. It is not directly related to LD’ing.
As I said the problem with WILD is that you remain aware durring the transition from awake to sleep. What happens is that you can then see, hear and feel things from the real world and from the dream world. Your mind trys to make something understandable out of all that information, and puts together what it can. It can be scarry, or it can be funny. That depends on you. If you expect it to be very scarry, then it will be, if you expect it to be funny, then it will be funny.
Fact is, if you have never had the old hag so far in your life, then chances are good that you will not have it even if you do WILD. I have never had it, and I have had a lot of time both before and after doing WILD.