We will find out exactly which of the Martin lines we belong to very soon. My brother a direct Martin has tested Big yDNA with FTDNA we know we definitely belong to Joseph J Martin born before 1760 and died in Richland County, SC.
My grandfather said that Joseph was born in Ireland, but our Martins originated in Scotland. Some of our SC cousins think our Joseph was born in Virginia. On Geni, we have our Martins originating from Finland, then migrating to Virginia. I do know my great Uncle married his Martin cousin from Valentine Martin's lineage. My grandfather told me he moved to Texas, so he wouldn't end up marrying a cousin. He always said just about everyone around Mississippi is kin to us.
It will be interesting to see how my brother's DNA testing works out the Martin line.