The vibrations are part of the stage in a WILD, they vibrations don't help you recognise your dreams but indicate that you are entering a WILD. I'm not sure about SDFD's but HI stands for hynogogic imagery which is the imagery you will experience when entering a WILD or maybe when exiting a dream, it is a bit like watching a light show, different shapes flying around you and colours passing by, i've never experienced it myself but people have told me it has been like that for them.

Xyn, for your vibrations, this would be the part after sleep paralysis i guess and you were probably just about to enter HI by my guess but unfortunately i'm not a master of WILDs so i may not be able to offer the best help.