The large migrations from Scotland were in the 1600s, rather than the 1700s, though there was movement to and fro all the time. The first major migration was the Hamilton & Montgomery settlement of 1606 when very large numbers came from Ayrshire and surrounding areas.
The basic deal was that in 1607 the lands in Antrim and Down were declared forfeit to the Crown, following the “Flight of the Earls” when the previous rulers (the Earls) had fled Ireland. King James I decided to encourage Scots to settle in the vacated lands, so he granted land to existing major Scottish landowners on the strict understanding that they took large numbers of their kinsmen with them. In return for which they would all get subsidised rents. (Previous attempts to bring Ireland under control in the 1500s had failed because insufficient people had taken up the offer to settle there and had been outnumbered by the native Irish. This time the King was determined that sufficient numbers would go to eliminate that problem. The subsidised rent and availability of land in Ireland made moving there very attractive so hordes of Scots (and some English) went willingly. King James I was of course Scottish, and so most of these major land owners he made grants to were friends or even relations and in general loyal to him. So he felt he could rely on them). No-one was compelled to move. The motives, as far as the settlers were concerned, were simply economic betterment. The land in Co Antrim is identical to that in Ayrshire and surrounding counties and so for a farmer or a labourer it was a very easy and smooth transition to make. It’s only 20 miles from Ayrshire to the Antrim coast and so a very easy journey to make from a practical point of view too. You can read more about it on the following site:http://www.hamiltonmontgomery1606.com/
Around Ballymena, the major land owner was the Adair family, who came from Kinhilt, near Stranraer, Wigtownshire. He got his land grant in 1625 from King Charles I, successor to King James I, who had died that year. So if your family came from Ballymena, it’s possible that they originated in Wigtownshire, but that is just speculation as by the 1800s as a result of natural internal movement many of the population of Ballymena would have come from a much wider area.
You ask about researchers in Co Antrim. I live in Co Antrim and do local research. If you still need assistance, let me know.