Not wishing to take exception Jim but I did read the link you put up very carefully.

Here are the names of those mentioned:

King George V - attended the conference
Charles Stewart Parnell
H. H. Asquith - attended the conference
Lord Randolph Churchill
Andrew Bonar Law - attended the conference
Lloyd George - attended the conference
John Redmond - attended the conference
John Dillon - attended the conference
Edward Carson - attended the conference
James Craig - attended the conference
Lord Lansdowne - attended the conference
The Speaker of the House of Commons presided at the conference.
Terence MacSwiney
Éamon de Valera
James McNeill

So those being the ONLY names appearing in your link the question still stands - Who is the T.P. mentioned in the song which I now note is not an excellent example encapsulating an actual historical event, but a satirical view of an actual historical event.

On the Lord Leitrum thing the only real piece of evidence is the written statement by his Housekeeper in the form of her letter dismissing the allegations as nonsense - everything else is hearsay and unconfirmed gossip.