Rev Henry Crooks and his father William Crooks

Brief research suggests these 2 Ministers were Presbyterian. The Presbyterian Historical Society in Belfast keeps records of all Presbyterian Ministers known to have worked in Ireland. That usually includes a little personal information as well as career details. You could e-mail them to see what they can tell you.

Both Ministers should have had a degree (not necessarily a theology degree in those days). As Presbyterians they would not have been able to study for the Ministry in Ireland, and so would have gone to a Scottish University. At that time 4 were functioning: Glasgow, Edinburgh, St Andrews and Aberdeen (callled Marischal College then). Those universities all keep quite good records of students going way back to the 1600s. If you e-mail them you might find some information there.

Presbyterianism was founded in Scotland and brought to Ireland by Scots settlers in the 1600s. In the early years they were able to have a reasonable relationship with the Church of Ireland and were often able to use Church of Ireland churches for their services, later in the day (after the COI congregation had left). Then in the 1630s - 1650s the COI Bishops expelled them all and most had to leave Ireland and go back to Scotland. They were able to return around the 1660s but it was often many years before they were able to build any churches, so records for that period are a bit thin on the ground.

Thank you I do know that one of them was apparently there during the siege of derry and was a non conforming minister would you be able to tell me what that means? 

The established church in Ireland (ie the state approved church) in the 1600s, 1700s and mid 1800s was the Church of Ireland. Those of other denominations eg Catholics, Baptists, Quakers, Jews and Presbyterians were regarded as not conforming with the state religion. So they were non conformists. Yours appear to have been Presbyterian (and so most likely of Scottish birth or origins) and therefore you should focus on those records.