I would suggest that "They are not only lawyers" could be "Ní hamháin gur dlíodóiri iad" ["Not only that are lawyers they"].
See this example from http://www.focloir.ie/ga/dictionary/ei/neighbour:
"they're not only our neighbours but also our friends - ní hamháin gur comharsana dúinn iad ach is iad ár gcairde freisin iad"
I don't know if this construction can, not only introduce an "ach" clause, as above, but also be used absolutely.
Someone else might be able to enlighten us further.