Hi longberry,
Can't help you with parents too much but maybe some clues.....
You've probably looked before but just in case, these are all the children born / baptised to Alexander Budge's in Caithness 1760 to 1798. (Using Soundex threw up a few more but nothing likely) I've shown the mother where known, otherwise not stated (source .. SP) .....
1 01/08/1785 No name given Latheron 038/ 0010 0229
2 20/04/1788 ALEXR. Latheron 038/ 0010 0244
3 01/01/1764 ELIZ Latheron 038/ 0010 0104
4 05/11/1769 ELIZABETH Latheron 038/ 0010 0137 (probably the one you know of)
5 01/01/1780 JAMES Latheron 038/ 0010 0212
6 02/02/1782 JANET Halkirk, CHRISTIAN CORMACH 037/ 0010 0052
7 01/01/1775 JEAN Latheron 038/ 0010 0167
8 01/09/1793 JEAN Latheron 038/ 0010 0282
9 01/02/1784 JOHN Latheron 038/ 0010 0221
10 01/03/1788 KATHARINE Bower, GOW FR 141 034/ 0010 0218
11 06/03/1791 MARGT Latheron 038/ 0010 0263
12 19/01/1791 SARAH Reay, MARGT. MILLER 040/ 0010 0125
Only 2 Alexanders born 1700 to 1750 in Scotland
1 17/02/1734 parents JOHN BUDGE/JANET BAIN Watten 042/ 0010 0105
2 14/10/1744 parent JAMES BUDGE Wick 043/ 0010 0221
and the closest I can find to Margaret in Scotland, the only Margaret is too young but any of these may be a clue......
1 11/09/1723 DEIRAN, WILLIAM parent Wm Thurso 041/ 0020 0017
2 29/05/1720 DEIREN, JOHN parent Jn DEIREN Wick 043/ 0010 0070
3 20/01/1712 DIRAN, ?- parent WILLIAM DIRAN Wick 043/ 0010 0031
4 25/04/1708 DIRAN, ALEXR p WILLIAM DIRAN Wick 043/ 0010 0020
5 03/11/1710 DIRAN, ALEXR p JOHN DIRAN Wick 043/ 0010 0027
6 04/05/1712 DIRAN, ANDREW p JOHN DIRAN Wick 043/ 0010 0032
7 12/09/1708 DIRAN, DOD p JOHN DIRAN Wick 043/ 0010 0022
8 14/02/1714 DIRAN, ELSPET p JOHN DIRAN Wick 043/ 0010 0037
9 03/11/1710 DIRAN, JAMES p WILLIAM DIRAN Wick 043/ 0010 0027
10 30/11/1712 DIRAN, JANNET p WILLIAM DIRAN Wick 043/ 0010 0033
11 26/02/1716 DIRAN, JANNET p JOHN DIRAN Wick 043/ 0010 0042
12 31/10/1714 DIRAN, JOHN p WILLIAM DIRAN Wick 043/ 0010 0039
13 15/09/1704 DIRAN, MARGARET p ALEXR DIRAN Wick 043/ 0010 0012
14 07/06/1704 DIRAN, MARJORY p WM DIRAN Wick 043/ 0010 0011