Have checked the births for Sutherland looking for your Johan and only find one child born of that name in 1867. She is Johan McDonald, born 27 November 1867 at Durness, daughter of John Mcdonald and Mary Stewart.

I then looked for your Johan and found what may be her in Elgin. An Alexander Mcdonald, aged 61 years, born in Inverness, was living with his wife Isabella and a granddaughter, Joan McDonald, (Joan and Johan are the same name)in Elgin in 1881. Interestingly this family had a boarder, Isabella Scott, aged 1 year, born in Elgin.

Hope this helps.
Christine Stokes