HELLO, PLEASE SEE RESPONSE BELOW TO YOUR QUESTION...
From what my father's been able to tell me he isn't sure weather it's a Scottish or Irish. My dad doesn't know much if any family history from my dad's side of my family. Except he thinks that we might have some Jewish relatives on his side and some Native American(Indian). Now on that' I have some Native American(Indian) on both sides Moms and dads not just my dads side (don't know what type i.e Cherokee or Osage ??) I kinda/sorta remember my grandmother saying that we have some Polish in us, but confirming that went away with my dearly departed Grandma Minnie Estelle Metcalf.
My moms maiden name was Metcalf her mom Minnie Estelle and her father John Dotson Metcalf, she has 5 siblings Carol Sue, Anna Laura, Jo Ann, Micheal David and Ronnie Gene, I was named after her sister Carol Sue which is deceased having died of (unknown type) Cancer, her brother Micheal and his 1st wife gave her a niece Leah Lynn who gave her a great niece Maria and a great nephew Antonio, Leah has of this year recently deceased leaving her children in the care of her mother Jewel.
My mother doesn't know much of about her half of the family history, except that we have some Native American ancestry in us other than that nothing.
RE: Your questions about MCFARLAND/MCFARLANE/MCFARLIN families in USA....
By Y-DNA we are not related to "real" CLAN MACFARLANE folks....
There are 8-9 DNA related McFarland/McFarlane/McFarlin lines in the USA (Daniel McFarland of Worcester Massachusetts, Duncan The Weaver McFarland of Augusta Co Va, William McFarland of Orange Co NC, John McFarland of Boothbay Maine, Francis McFarland of Pennsylvania, and others) they mostly immigrated from Ulster, Northern Ireland, especially Tyrone....the Y-DNA (male) of these lines runs R--L1335, R-L1065, R-Z16325, R- S744, S764 and FGC28985....all came to USA between 1718 and mid-1800s, they can be found in Mass, Maine, Shenandoah Valley, TN, KY and NC...if a male McFarland is unavailable for DNA testing females can also test with Family Tree DNA by using the Family Finder test, which will generate a list of autosomal matches
Suggest if possible you have a male McFarland in your line test Y-DNA at Family Tree DNA and once completed join the Macfarlane DNA Project at Family Tree DNA, those just above and below will be your closest matches.
Mcfarland/McFarlane/McFarlin, as noted above, have the R-S744 SNP, this is likely a signature SNP of Siol alpin ( see Rob Spencer analysis of the Clans of Siol Alpin at his site scaledinnovation.com).These McFarland/McFarlane/McFarlin lines are not by DNA of Clan MacFarlane, these lines are either Gaelic or Pict in origin, where MacFarlane are Strathclyde britons.
A single man, in Scotland ( if Pict) or Ireland (if Gael), at about 400-600AD, the first male in these lines with the SNP mutation of R-S744...
that he survived in some pretty rough times, not just survived but had children who survived...his descendants founded some very Important Clans still existing today in Scotland ...was he King Alpin ( as traditionally claimed) or perhaps Fergus, who can say....
On Geni search for " Original Y-DNA McFarland " for a list of DNA related McFarland/McFarlane/McFarlin lines in the USA....also on Facebook as "Hidden MacGregors ", posts on history and Y-DNA origins.