Hi Gallus. You may find the following book interesting: The Lamont clan, 1235-1935 (1938) by Hector McKechnie. I'll quote a portion below (pp. 37-39):

Of what tunes were once played on the clarsach Laomannach and its fellows one can have little notion now. The harp music of the Lamonts has been lost for ever, but of the pipe music there are at the least five tunes of which the air is preserved, with three more of which the memory survives (or did in the last generation). Its value is immense for the recapture of the spirit of the old highlands. As Neil Munro has said, the piper who can fill the bag at a breath may “have parley with old folks of old affairs. Playing the tune of the ‘Fairy Harp,’ he can hear his forefolks, towsy-headed and terrible, grunting at the oars and snoring in the caves; he has his whittle and club in the ‘Desperate Battle,’... where the white-haired sea-rovers are on the shore, and a stain’s on the edge of the tide; or, trying his art on Laments, he can stand by the cairn of kings, ken the colour of Fingal’s hair, and see the moon-glint on the hook of the Druids!” And now for the tunes which should move the Lamonts to have converse with their past.[40]

The first to be printed was “Captain Lamond’s March,” which appeared in a collection by a Black Watch pipe-major in 1869 (plate 5). It was but eight years since the officers of that regiment had renewed the inscription on the tomb at Winchester Cathedral to Captain Colin Lamont of Monydrain, who had served with it from 1787 till his death in 1802. It is thought to have been in his honour that the "Spaidsearachd Chaiptein MhicLaomainn” was composed. In the Cowal Collection of Modern Highland Bagpipe Music, which is undated but was probably produced about 1900, appear a further march, “Ardlamont House,” and a quickstep, “Lamont of Knockdow,” both self-explanatory. To the latter family relates also a march, “Toward Point,” by Pipe-Major Brown, 1st Gordons, in Henderson’s Tutor for the Bagpipe, which seems later in date, and a “Knockdow,” by Pipe-Major John McColl, Glasgow, which was published in a Cowal collection of 1932. Of unpublished tunes there is reference to a lament “The Exile’s Lament,” or “Cumha an Fhograich commencing “Sa Mhic Laomuinn tarruing t-aonarf" and a salute, “A Thousand Welcomes to thee, Lamont.” At least some of the words of the latter in Gaelic are as follows:—

“Mhic Laomainn ceudfailt’ dhuit,
’O Thollart gu d’ airde,
Inbhirinn ’s an Cul-trathach,
’S a' Mhealrach nam pdisdean.
O hururaich 0, hererich,
O hururaich 0, hererich !”

The translatable portion may be rendered somewhat like this: “O son of Lamont, a hundred welcomes to thee, from Toward to thy Ard (i.e. Ardlamont), from Inveryne and (?) Colintraive, and from Melldalloch of the children,” the latter epithet being now unintelligible. It is of the utmost importance that the tunes of these should be recorded before they perish. Somewhere in the wide world must be ears that have heard one or other, and it is to be hoped that someone will commit them to script and communicate them to the Society. [41]

Plate 5 - Captain Lamond's March

[40] The Lost Pibroch, pp. 3-4.
[41] (Wm.) Ross’s Collection of Pipe Music (1869), p. 65; Stewart’s Sketches, i, 479, in L.P., 1339, p. 391; and see below, p. 391; Cowal Collection (Dunoon, undated), pp. 32, 34, and (Dunoon, 1932), p. 16; Peter Henderson’s Collection (Glasgow, undated), p. 66 (all three to be seen at Knockdow); Frank Adam, The Clans, Septs, and Regiments of the Scottish Highlands (1908), p. 410 (2nd edn., 1924, p. 418); see note 42 below.
[42] Fionn (Henry White), Martial Music of the Clans (Glasgow, 1904), preface and pp. 156-8.

Maybe you've already found this, but I think it answers your final request (for Captain MacLamont's March) while noting that your first and second requested tune were unpublished as of 1938 and in danger of perishing.