Ó Murchadha or Ó Murchú is pronounced 'O'Murrakhoo'.
Ó Murchú
The English surname Clifford has no Scottish Gaelic form.
It is Goisdealbh which is the origin of the surname Costello(e).
'Kerr' is not a word in the Irish language.
There's no Irish Gaelic equivalent so it doesn't change even if the surname has a Gaelic form. 'Carrie Ní Bhriain' for example. Scottish Gaelic:?
Ó M'wael-ownig (Munster)
Assuming you mean the surname 'Hunter', the Gaelic form is Mac an t-Sealgair. The pronunciation would approximately be 'makhk uh tchelagir'.
This English surname apparently has no Gaelic form.
Paul Murphy - Gaelic footballer - was born in 1979.
John Murphy - Gaelic footballer - died in 2009.
Tommy Murphy - Gaelic footballer - was born in 1921.
Tommy Murphy - Gaelic footballer - died in 1985.
It's not Gaelic so why pronounce it.