Paling in Ulster
In Search of the Ulster Palings
With the DNA evidence pointing strongly towards a link between Pelan and Paling, this broadens the search of the Irish records to include similar sounding names (e.g. Paling & Palen). If we can find these surnames in Ulster or more specifically around Lisburn then this would be very convincing evidence for the progenitor Pelan's lineage.
Wardens of Lisburn Cathedral
There is a book by the Rev. Carmody  which lists, amongst other things, the church wardens of Lisburn Cathedral since 1667. Of particular note are the following names, in reverse chronological order:
1820 - George Pelan
1809 - Richard Pelan
1798 - James Pelan
1697 - Matthew Pailing
So there was indeed a person called Pailing living in Lisburn ! Is this proof of the origin of the Pelan surname? It may be but it is not conclusive by any means. The name Matthew is a recurring theme in the Palen line but one cannot infer anything from this possible coincidence.
Turing to the available Muster Rolls  of early 17th century Ulster, we find ''Andrew Pallein (In the town of Bangor for the Viscount of Clannaboyes)''.
The Viscount of Clandeboye was the Scot James Hamilton.
Irish Flax Growers List (1796)
This has a John Pallan in Armagh.
Cromwellian Adventurers (circa 1650)
John O'Hart's "Pedigrees of Ireland"  has a list of 'sirnames of the Adventurers for Lands in Ireland''. On it is contained Pallin. Unfortunately I haven't found the original source for this surname. This is important because, assuming the surname is correct, it needs to be established if this individual took up land and, if so, where. The surname doesn't appear in  which has two comprehensive lists in its appendices; "Original Investors" and "Adventurers who Drew Irish Land".
Conway Papers / Calendar of State Papers (17th century)
Three generations of the Conway family governed their Lisburn estates as absentee landlords with the aide of resident managers (e.g. Sir George Rawdon, a Yorkshireman). Much of the correspondence between their estate managers and the relevant Conway are preserved in public archives or transcripts  as much related to government business.
There is a letter from John Hartnell to Lord Conway (Edward, the 3rd Vicount Conway) written on the 29th March 1661  which goes:
"Mathew Pallan desired me to give account to your lordship in what condition 'Snow head' and the gelding are in, for he made a full trial betwixt them upon Wednesday".
Sir George Rawdon to Viscount Conway and Killulta writes on the 12 Dec 1666:
"P.S.—Mathew has just come to me and asked if provision should be made for building a house for him at Lambegg, and for a stable. I said it was a troublesome time and asked what sort of house he required. He said he thought it best to be fitted for an inn. I desire your lordship's pleasure as to what you will disburse. I doubt £200 or £300 will but serve for such a house and stable. "
A list of the officers and soldiers in Viscount Conway's troop of horse (written around 26 June 1667) includes Mathew Palling.
Note the implication that Mathew is perhaps a stable master or horse trainer when not a soldier. Another letter, this time from George Rawdon to Lord Conway (17th Dec 1673) , contains this:
"I met Matthew Paling on the way to Dublin with money to discharge your bill for Mr. Crabb and with 50l. for scores in Dublin. He took the opportunity of Sir W. Tichburne's troop's remove, and I wrote to Lieut. Bolton that two or three of your troop should meet him at Drogheda, for exchange to Dublin could not be got. "
Can we be sure that Mathew Pallan (in 1661) and Matthew Paling (in 1673) are the same person ? A letter from Sir George on the 27th Dec 1673  says:
"Matthew is come back and I sent him to Portmore to-day to see how the horses and colts are."
So it seems that this Mathew also has an interest in horses and is probably the same person. There are numerous other references to Mathew in correspondence about horses.
Lisburn Cathedral Records
It seems sensible to look through what remains of the local church records (or copies thereof) to see if Palings can be found. In the Lisburn Cathedral books  we find early baptism records:
1670 Penelope dau of Mathew Pelin of Lambeg - 12th Jan 1670
1671 Mary/Marg dau of Mathew Palin of Lambeg - 24th Jul 1671
1672 Mathew son of Mathew Pealing of Lambeg - 27th Nov 1672
1674 Robert son of Mathew Pealing of Lambeg - 11th Apr 1674
1677 Ellin dau. of Mathew Pelin of Lambeg - 7th Nov 1677
We might reasonably infer that these Mathews from Lambeg are one and the same person. So here we can see, in the same record book and over a matter of just a few years, three different spellings of the same surname - Pelin, Palin and Pealing. The name therefore was quite elastic in its spelling even in the 17th century. A little further on in time, one assumes the son Mathew above has his children baptised:
1696 Charles son of Matthew Palin of Lambegg - 9th Jan 1696
1697 Catherine dau of Matthew Palin of Lambegg - 29th Jan 1697
1699 Matthew son of Matthew Palin of Lambeg - 23rd Feb 1699
1702 Katherine dau of Mathew Pelin of Lambeg - July 7th (?) 1702
While the surname is more consistent, neither the spelling of Lambeg nor Matthew is stable which gives the impression that spelling conventions, or perhaps adherence to them, were not the norm.
Summary of Findings
Here is documentary proof of people with a surname like Palin / Paling / Pallan deeply associated with 17th century Lisburn and Lambeg. The DNA evidence which initiated this wider search surely suggests that these were the progenitors of the Pelans in Ulster. We still do not know if Paling changed to Pelan "naturally" or if it was influenced by a pre-existing surname in the Lisburn environs.
We also do not yet know whether the earliest Mathew Paling was an immediate native of England or if he was a descendant of an earlier English migrant. While we do not yet know the precise whereabouts of his line either - the genetics shows a clear common origin with the Nottinghamshire Palings. We also know that the Conways brought men over typically from the north of England (e.g. Yorkshire) so everything is remarkably consistent.
It should be noted that in the Freeholder's records of the early 19th century there is still a Matthew Pelan in Tullynacross (Lambeg) and whose landlord is Francis, Marquis of Hertford - the inheritor of the Conway estate.
Lisburn Cathedral and its Past Rectors, Rev. W.P. Carmody (1920)
The muster roll of Co. Downe c.1631, Transcribed & indexed by Margaret Williams, (1989)
Calendar of State Papers Relating to Ireland, 1661
Calendar of State Papers, Domestic, 1673
PRONI, Lisburn Cathedral Records MIC1/3/1
Pedigrees of Ireland, Vol. 2, John O'Hart (1892)
English Money and Irish Land, Karl S. Bottigheimer, Clarendon Press (1971)