i know it means the message has been delivered to the iDevice not Read but my question is: If the receiving iDevice doesn't have internet/3g/4g/lte connection, will the iMessage status say Delivered on the sending iDevice too?
No. It'll try to deliver as text if you have that option enabled. If, for whatever reason, it can't be sent as text either then it'll notify you with a red exclamation that there was a problem sending.
it doesn't say any status and it's blue. Does it mean the receving iDevice has no internet connection? so to sum up
Delivered: receiving iDevice has internet connection and the message is received but not read
No status, blue message: receiving iDevice has no internet connection and the message is in iCloud waiting to be sent when the receiving iDevice has internet connection again?