That sounds like great progress.
Don't forget, however, that FamilySearch only has an index to all this. The originals are available online at
www.scotlandspeople.gov.uk, and they may contain additional information that is not included in the index.
If you are anywhere near a LDS Church family history library, I strongly recommend going there and arranging to rent the microfilms of the Strathdon parish registers. Go through them carefully, noting all references to McHardys, including those where the mother was a McHardy, and those where McHardys were witnesses. This is by far the best way to see the pre-1855 records, because you often pick up snippets of information that you wouldn't see if you just download all the McHardy baptisms from Scotland's People, and it's cheaper. There should be a list of LDS FHLs on the FamilySearch web site.
Also that the other two sites you mention are transcriptions, not originals. Again, the originals can only be accessed via SP.
It will probably be worth while, if and when the Kirk Session records go live on SP, taking a look at them to see what additional information is available about the illegitimate births.