Some guesses as to the missing words, based on the many versions I have seen whilst getting a singable version together :
Verse 4: Often he is welcomed with 'coal and candle-light' i.e. the house is warmed up and lit up for a special visitor.
Verse 10: they booted him and spurred him as he was wont to ride ( i.e. they make it look as though he fell off his horse)
Verse 16: that is now the willow wand ( ie. willow twigs)
Verses 27,28 : blood came gushing out ( an old superstition - when the murderer approaches the corpse of his/her victim, the wounds bleed)
Verses 31 & 32. Hollow - I agree with previous posters - 'hollin' the Northern word for Holly.
The rest of the missing words I can't help you with. Sorry.
Mary