Here's my guesses:
Queen of the Lonesome Isle:
Banríon an oileáin chumhaigh OR Banríon an hinse cumhaí
misfortune of the world:
mífhortún an domhain
My source for lookup was http://www.teanglann.ie/en/, using both the dictionaries and the grammar database. I could still have errors....
There are two words in Irish for "Island" (and both translate for the diminuitive form): oileán and inis. Oileán is masculine and inis is feminie. This accounts for the different treatment of the adjective in each case. In both cases, the genitive of the noun is used since this is a possessive construct.
The Irish word tubaiste means "tragedy, calamity, disaster" and was the first word I found in one of my dictionaries under "misfortune" but the database provided the alternative mífhortún which I thought carried the truer meaning of what you were asking about. The genitive for "world" was used, domhain, again because of the possessive construct.
I hope that is helpful. If anyone has any comments, corrections, suggestions, or complaints, feel free!
Dale D