Vicar people look at me a bit funny sometimes because I'm constantly wittering on. They don't realise that I got into the habit because I used to have a blind pony and he needed to know where I was. Half the time I don't realise I'm doing it. I'm not sure what dhorse thinks about it, probably "FGS shut up and give me some peace, you mad woman" .
I'd also be very wary , my old TB mare was a sneaky biter and on one occasion nearly gave my mum a mastectomy ! Very painful especially towards the end of her life when she had a nasty stable accident and her upper teeth were a bit jagged for a few days .
I don't want to appear blunt but since no one else has replied yet, to the best of my knowledge horses that lick skin are trying to get to the salt and may well have a mineral deficiency. Easily remedied with a salt lick.
I would be a bit weary of letting a horse lick my ear, horses can easily go from licking to biting, especially something tempting that sticks out like an ear. The horse needn't be aggressive to do this, it could just be trying to groom you back but horses can often misjudge their strength.
The best indicator that a horse has bonded with its handler/rider is the horse's willingness to take its cues from the handler/rider. For example, the horse is in hand, frightened by something behind it but accepts the handler's reassurance that all is well and there is no need to run. Or the horse is unsure about an object but accepts the rider's aid that it is OK to approach the object.