I am not quite sure what you mean by LL and NN but there are issues with both phonemes. This broad l is what Gaelic linguists sometimes call a dark l and sometimes write as L in pronunciation guides. For example Am Faclair Beag gives /saLəN/ for this word and Mark says
Broad l is like a hollow ll as in 'full ' with the tongue touching the upper teeth.
It is often even more 'dark', almost as if you are swallowing your tongue.
As for the nn, all the sources I have looked in fail to distinguish between a stressed syllable and an unstressed one. In my experience what they say is basically correct for an nn in (including at the end of) a stressed syllable, but simple wrong in an unstressed position. From what you say (and I cannot get from here to the recording) and from my own experience, it is pronounced as an ordinary English n but with the tongue touching the teeth (as in th in English, d and t in Gaelic).
If anyone knows specifically about the pronunciation of nn in unstressed syllables, or any references, please post.