Petit mal seizures immediately came to my mind when you described the short "blank-outs." Has she been tested specifically for petit mal epilepsy? Just because the doctors have not seen an episode does not mean it isn't happening. She may need to wear a tracking device all day and in her sleep at some point. My friend's son did, so that doctors could finally trace why he was having "white-outs" as he called them (he is far older than your child, though and his white-outs were due mostly to stress).
It sounds as if you may need to be more assertive with the doctors who say she is fine. If she is having these incidents repeatedly each day, she is not fine.
However - and it is a huge "however" --it also sounds possible that you are searching so hard for a diagnosis that you are out there shopping the Internet for possible conditions that fit your child. Be very careful about that; it's extremely easy to get scared to death by dire things on the Internet.
Instead, keep a detailed diary of every minute of her day and everything she does. Keep it over a month or so and then see the doctors with it. You say you've been told she has sensory issues -- but did the doctors then DO anything with you about how to work with those sensory issues? It sounds like you've been told a diagnosis and nothing else!
The blank stares (and the violent reaction when you try to touch her during those stares) sound a lot like a form of epilepsy BUT many of the other things you describe sound like normal things a child her age might do: Kicking in her car seat. Kissing and hugging other kids freely. Being very shy and mumbling around adults. Even licking -- I've known kids this age who do lick others for a while then stop doing it; its a great way to get a reaction from adults. (If you react to the licks by leaping to intervene and saying, "No, no, we don't lick," that is giving her attention for the behavior, which might be exactly why she keeps doing it--calm down and ignore it instead.)
As for not falling asleep, you say you have tried everything, but it also sounds as if you have tried too much, too hard -- has she ever had a very, very consistent bedtime routine that never changes? Or have you tried so hard to find the one thing that might work, that you keep changing what you do each night or every few days, so she never gets any sense of a regular routine? It's very easy to fall into the trap of "Maybe tonight it will work to swaddle her" then "That didn't work yesterday, tonight I'll move her bath time instead...." That means she never knows what to expect or what routine signals to her that bedtime is approaching.
Get some good books on child development from your library and study up on her age for things like the sleep issues, the extreme affection with other kids (pretty normal for some children), the aversion to talking to adults. You may find she is really quite normal.
But for the blank-out stares, yes, I would be more assertive about pursuing that with doctors. If you go to the doctors with every little normal thing, as if it's a problem, they frankly will take you less seriously about the things that ARE serious, so try to ramp back your own fears and be focused on just what seem to be the real issues--the blank stare incidents and the sensory issues.