I have access to Ancestry.com, which has transcripts (but not images) for the 1861 and 1871 censuses.
For 1871 it lists a Rodrick Mclennan, age 41, shepherd, living at the shepherd's house in Barvas, county Ross and Cromarty, born in Kintail, Ross-shire, together with wife Helen (age 43) and children Hugh (18), Peggy (14), Duncan (15), John (12), Helen (10), and Christina (8).
For 1861 this person is listed as Roderick Mclennan, age 31, farm grieve, living at Upper Barvas in parish of Barvas, born in Glenshiel, Rossshire, with wife Helen (age 34) and children Hugh (11), Duncan (6), Margaret (4), John (3), and Mary (2).
Appears to be same family as your emigrants. Ages of John and Helen slightly older than on passenger's list; two of the children on passenger list are also on 1871 census (oldest child Mary is absent), and the old-enough child is on the 1861 census.
The citations (for those with Scottish census access elsewhere) are Parish: Barvas; ED: 4; Page: 7; Line: 4; Roll: CSSCT1861_11 and Parish: Barvas; ED: 4; Page: 1; Line: 15; Roll: CSSCT1871_15