Hi Brylio
There is this reference to a marriage/banns here
https://familysearch.org/pal:/MM9.1.1/XTRK-JYXHard to say if connected without more info really.
The birth/christening entry that you have shows on the OPRs doesn't it on Scotlands People. There looks to potentially be one other entry in the OPRs in 1805, with those parents' names, but this shows in Edinburgh
https://familysearch.org/pal:/MM9.1.1/XT5Z-L8GIt is always frustrating when you are only able to find just a few records in the period pre 1855. Lots of reasons for this. Remember also that only about a third of births and marriages were recorded in the Old Parish Registers which were for the established Church of Scotland, ie presbyterian. Other denominations are harder to find entries for in the old records.
Do you know what Donald Fraser's occupation was from any of Alexander's details? His 1810 entry, were there any family surnames for witnesses (if a christening entry)?
There is a Donald Fraser having children in Laggan after 1812. But this is from a couple who married in 1812 and wife called Janet Fraser.
Kirk Session minutes etc are only searchable in person. Nothing is currently available online for these types of records (ongoing project at Scotlands People...).
Monica