That is fine. You will get real coins in due time as well. 
are you saying Dogecoin isn't a real coin?
The dogecoin hype will probably only last for at maximum 6 months, there are too many flaws create by it's too good-to-be-true rules. So, invest in the more 'stable' coins such as Bitcoin and Litecoin
no, Dogecoin is eternal
Doge will never end
if you are referring to the no cap thing as I think you are, doesn't matter because as time goes by the rewards will be smaller and difficulty higher producing less and less doges which won't really make difference
Doge has something that other alt coins don't, they have the possibility to get adopted by meme based websites as a tipping source