Hi,
As far as I have been able to test the "Syncing" is only "Display on all devices" and not a full on "Copy actions across devices".
This means deleting it on the iPad or iPhone does not remove it from the Mac version (Nor Stop it appearing if the Mac was Off).
The "Read" and "Delivered" subtexts seems to be in a world of their own around the edges of this issue at present. So much so I tend not to pay any attention to them.
With regard to the second post
The iCloud ID does not have to be the Apple ID you are using in iMessages.
It may also be a valid AIM Screen Name that you have logged in.
This and a GoogleTalk login will not have "Read" or other info posted in the Chat window as to it's delivery status.
If you are talking about Mail across different devices not apparently keeping up that is a separate issue.
10:25 PM Thursday; November 8, 2012
Please, if posting Logs, do not post any Log info after the line "Binary Images for iChat"
iMac 2.5Ghz 5i 2011 (Mountain Lion 10.8.2)
G4/1GhzDual MDD (Leopard 10.5.8)
MacBookPro 2Gb (Snow Leopard 10.6.8)
Mac OS X (10.6.8),
Couple of iPhones and an iPad
"Limit the Logs to the Bits above Binary Images." No, Seriously