Cracknel = hard toffee
magnolia is an off-white shade very commonly used as chepa paint for walls throughout the UK. Not particularly Yorkshire
Garth (Home Close in Southern England) is a small enclosure close to the farmhouse where baby or sick animals (sometimes pigs) are kept
mashing = brewing / stewing. In the rest of England it is used for the 1st process in making beer
The Northern Union is another term for Rugby League and, by association, where this is played (as opposed to Rugby Union)
Quaggy = boggy (from normal English "Quagmire" = bog
slummocky = messy or untidy
huffed is just the [verb/past tense] of huff in use throughout UK ("she went off in a huffed").

:-)