The family of MacDougall of Dunollie

[Seumas MacThómais]

I am seeking a current pedigree of the late medieval chiefs of the
MacDougalls in western Scotland. The most recently published material
I have seen is the research done by Dr. Jane E.A. Porter of Edinburgh
University's Divinity School, much of which she has included on this
website:

http://www.div.ed.ac.uk/thebreadalba

The core of this work is a remarkable series of letters from the
Campbell lairds of Glenorchy, preserved in the National Archives of
Scotland, which Dr. Dawson transcribed and published in 1997 (this are
all available at the website, and make great period reading). The book
version is: Clan Campbell Letters 1559-83, (Scottish History Society,
5th ser. Vol 10, Edinburgh, 1997).

This book (and website) provides two generations of MacDougall chiefs:

1. Alexander MacDougall and Isobel Campbell, had two sons:
a. John MacDougall, 14th Laird of Dunollie, d. 1562; m. Margaret
NikVane, but died without issue.
b. Dougall MacDougall, 15th Laird of Dunollie, succeeded 1562, d. ca.
1591. Married an unnamed daughter of Dougal Campbell of Auchinbreck.

This latter couple were the ancestors of the later chiefs.

My questions are: who were the ancestors of this Alexander above (was
he the son or brother of John MacDougall of Dunollie, who died about
1535?) and to what Campbell family did Isobel belong?

Thanks in advance for the assistance.