When I read your post it felt like I am reading my own problem. My son is also EXACTLY the same like u, aincluding age.
He also puts things in mouth and spits out. Doent chew, just swallows...etc..etc..
But otherwise he is 200% ok child and was always carried excellent height and weight.
This whole thing started becoz, I work and my MIL used to find it easy to feed him pasted stuff. He got used to it.
What I can suggest u is:
1. Dont just give him rice dal, give him every thing u eat by mashing it in a food processer. That way, atleast u r assured that he doent loose out on vital foods.
2. Stop Cerilac and start giving him Cerimeal (Nestale product for kids above 2 years)
3. Keep giving him stuffs like wafers, Kurkure etc...let him spit ..
One last word of advise is that, there are many ki8ds who start like this and become 'all fine' in due course of time.. so dont worry.
Please let me also know, if u try some thing good and if it works..