Sensory Seeking in 2 Year Old?

Hi Everyone, 

So I am here looking for some advice, as we are beginning the process of going down the route of a diagnosis for our son. At the moment we have sent a referral to a paediatrician, but we are waiting to hear if they will accept our sons case and investigate or not. 

I am wanting to ask about sensory seeking behaviours, particularly orally and whether these are just normal 2 year old behaviours, or if they are something more. 

So our son mouths EVERYTHING, he excessively dribbles and is constantly chewing on things. He chews wooden toys to the point where he gnaws away at the wood they're made from, scratches the paint off them, he licks everything and he also bites us gently. It doesn't seem like this is to hurt us, it's more like he does it when he gets too excited. When I say he excessively dribbles, I mean it's to the point where he has to wear a bib ALL of the time, he gets through 3/4 bibs a day and the bibs soak through onto his outfits and we have to change him. I mean through jumpers, t-shirts and right down to his vests. He drools a lot and he doesn't seem to have any awareness of himself doing this. 

More recently, he has started licking the TV when bright colours come up. He licks specific points on the TV, like where the bright colour is. And he also looks right into lights and licks them as well. He is constantly putting his face into our christmas tree and licking the individual lights on there too. If his baby sister is playing with a toy which lights up, he'll lick that. It's like he licks colours and that's his way of processing them. Is this an actual thing? Is this something which is a common behaviour in toddlers, or is this something else? 

Any advice would be great! 

Thanks!