There are all sorts of riffs, stabs, squeaks, slides, knocks, chords and strums etc in the Guitar Pack. Whilst there is no 'Reggae' specific Program there are quick and slow chords, both electric and acoustic and one called 'Strum' which should do the trick. But ... there's probably more to it (Note: I'm no expert ... but just had a play :) ) ...
a. In Sound Center you have Tone, Resonance, Tremelo, Tremelo Rate, Panner, Panner Rate and FX Amount to play with. Defaults are quite heavy on the FX which is effectively delay so you might like to turn that down for a Reggae stab.
b. There are Amps (e.g., TH2 (included in Sonar)) to further hone the sound you're after.
c. Because Sound Center is audio multisample based you may have to shorten/extend / fade out / compress i.e, tweak the notes/chords to get the desired results.
Reggae stabs wre pretty simple - just a quick strum / release.
The Mylie one however, which has a lovely tone, would probably need quite a bit more work (I suggest much easier on a real guitar / Fishburn TriplePlay). There's a bend in the first note, varying down/up strokes and varying lengths. Some longer than the 'quick chord' samples so I had a play in Melodyne, squeezing a 'slow chord'. The result was OK, but that was just one note!
So the jury is out regarding a recommendation - it depends how much effort you want to put in, although there is some OK stuff that'll get you going.
I only have DSF Steinway Grand Pianos an Guitars. $120 is a good price for the lot ... but then they were on Steam for $75 for the lot recently ($3.75 each) ... or $7.50 each individually.
General Forum opinion is that Steinway Grands Pianos are a 'go to' set ... the rest are only OK ... but that's a pretty good price ($6 each) for a vast set (bound to find some keepers) if you have the spare cash.
Bottom line - it could be tough to get the real feel of a guitar from samples alone.
(but Reggae strums should be achievable quite simply).
Very good video on Youtube (I'm too noob to post links) ... search:
Convincing electric lead guitar using synthesis