I lived at University with two Liverpool fans both from North Wales area
One from Abergele and the other from Connah's Quay
When i first met them they both sounded so Scouse to me, but as time wore on and there were other students from Toxteth, i could see they had a twang with some slang, but not full on scouse.
If they were down south people would assume they are from Liverpool though if they didn't know a truer scouse accent
The cockney accent is dieing.
There are towns in Essex, such as Southend, Basildon, Harlow etc that have had the London overspill and the accent is similar to cockney, but its not true cockney. Its become a common slangy estuary English
True Cockney is mainly spoken by the old generation. with so many ethnic groups now living in the east end and less white people the original accent is on the decline.
I myself speak with typical Essex accent, with a some hint of cockney as my grandparents were true cockneys and that side of the family sound London. but i have on some words a slight Aussie twang only occasionally, this is from travelling Australia and going back on holidays, then sharing houses and flats with Aussies plus playing Aussie rules for two years. Then working for an Australian company for a time. Just listening and hanging around with Aussies so much at times created a twang. Over the years its got less and less