thanks for the welcome! "passport acc" refers to the accompaniment crossing over to many rhythms so you basically hear the same acc being played for a great many rhythms. one passport acc is used for the kassa family of rhythms, lamban, diansa, fankani, diagbe, sounou, soliba, komafoli, soboninkun, noumoufoli, sofa, ngoron, fefo, moribayasa and still many more. another passport acc is used for the dununba family of rhythms, soli family of rhythms, mendiani, soko, tage, ngri, liberte, sorsornet, djaa, mamaya, gidamba, konden, and lots more.
these accs are swung differently for certain rhythms, even placed differently (i.e sorsornet). it's really hard to describe and notating it, even in a graphical form will not do it justice. it really has to be heard over and over with attention to the subtle placement of the tones. tempo also affects the swing. listen to a malian recording of sounou being played slowly and then accelerated. the change in swing is very noticeable. it is somewhat more subtle in other rhythms.
ghosting, as you pointed out, does affect the sound and feel of the rhythm. if you can hear the ghost notes then you are not playing the proper acc. if the ghost notes are completely silent, whether it feels right will depend on your exposure to the music, level of playing and the tempo you are playing at. at slower tempos you can play the ghost notes and still swing the notes although this can take quite some effort. at a fast tempo, you will not be able to do so. in fact at a fast tempo the ghost notes delay the player and drag the rhythm.
even if the player is extraordinarily good the swing will be affected in a way that also drags the rhythm. many rhythms have features which pre-empt the beat, which give it momentum. those features might include kenkeni patterns that play right before the beat or other parts to a similar effect. in many cases the djembe accs are swung in a way which slightly pre-empts the rhythm, giving an illusion of speeding up when in fact the rhythm is being maintained at an even tempo.
another thing i have noticed is often kora players (such as sekou keita, who you mentioned) play certain accs with a more pronounced swing. there could be different preferences linked to their first instrument. that might also answer your last question. but it naturally follows that all parts are affected by the whole. 'no man is an island'...
as to trying to describe several different types of swing, i'd prefer to wait until we are joined by many other drummers who are lurking around elsewhere. it's a very convoluted topic and needs to be illustrated by examples (i.e sound files), and even then only immersion in the music can truely give you that understanding. still it could be useful to have an idea of different ways to swing rhythms. we could really use the expertise of other players who have paid attention to these things. i'm sure that will happen in due course.