Thought I would chip in with a professional viewpoint. On the whole I think Coley 6 is giving fantastic advice particularly with the low impact fitness and doing progrssive resistance training but going easy on the intensity particularly to start off with. I agree that as a general rule using weight machines is probably a lot safer for you than using free weights. However just be aware that the quality of the design of the machines also matters. For example overhead press machines often put the shoulder in an awkward starting position (too horizontally abductrd is the fancy term) and this can strain a weak shoulder joint capsulr which ciuld possibly cause a subluxation or even a dislocation of a hypermobile shoulder joint. Personally I would suggest that if you decide to do weights for strengthening (and this is a good thing to do for your condition) that you invest in some profressional help to get you started and maybe for the odd review to ensure all the exercises will maximise benefit and minmise risk of injury

With pilates -probably all good! Yoga -well that comes in many guises so not all is bad but on the whole the last thing you need to be doing is making yourself more flexible! - so i would steer clear. Something like Tai chi is unlikely to do you any harm and can improve your balance and posture -all good . But other martial arts - definitely steer clear

With the diet advice this is beyond my scope. But health professionals generally endorse eating F & Js. I don't thnk it is true that omega 3 oil improves joint lubrication. However this group of fats appear to be generally beneficial for preventing and controlling chronic diseases and it may be that as they exert an anti inflammatory effect on the body this is why people with joint pain often seem to vouch for supplementing their diet. Using fish oil pills rather than injesting oily fish may not be as good -so often the way wiith "food supplements" and we need more high quality trials to be sure about the benefits at this stage of consuming omega 3 oil. So far no sign that it does any harm. Anyway take opinions on the nutrition issue as an educated lay person rather than in my professional capacity -a dietician is the best soirce of advice on this.