the gas smell in the morning is def some leakage. i used to hav that too. got it checked and turned out to be the gas pressure reducing kit in the engine bay was leaking (thx to my sharp sense of smell!!)
there is an overflow valve in the cng kit, maybe that is leaking, because it doesnt leak once car has started, only leaks "jab kit over hoti hai" (in layman mechanic's language)...