Doge - in two years this will be passé, the teenagers will have found something else to have fun with
Quark - the speed and security will attract Joe Bloggs, massive growth at some point is likely.
I would agree on LTC.
Doge - will depend on the community, I disagree with the assertions that it's all teenagers to me is seems like they are bringing people of all ages in. If they continue building at the same rate and get more support it the next 6months or so, it will stick and live on for a long time.
Quark - Speed is important but not critical (compared to everything else), security meh... nobody new the crypto world does an analysis of all the coins for who has the best security... All coins have a base of good security the foundation is sound... It's the bells as whistles that each coin adds. If any specific feature becomes a must have it gets added then. How they can use its and how well it's accepted is what brings people in.
I'm still waiting to see what's Quark's big pull is for non crypto people.