As to the rest of the terms in question:

"brankie-o" - refers to a spruce tree, meaning that the young soldier that the veteran is talking to appears strong and hearty.

"cantie-o" - means light-hearted or merry. The veteran is annoyed with the young man's flippant attitude and demeanor.

"furr" - furrow. [See explanation above by GUEST.Murray on Saltspring]

"Clavers" - the name given Bonnie Dundee by his enemies, usually "Bluidy Clavers." It is short for Claverhouse. John Graham was lord of Claverhouse before being created Viscount Dundee by James VII.