Since you have lupus and fibro, I would suspect you have a good rheumatologist in your corner.  If you don't, you must have some awesome PCP.  I would first and foremost, have a discussion with the rheumatologist.  If he/she is onboard with you having weight loss surgery, then you are good to go.

Second, you may want to reconsider the lap-band as your surgery of choice.  You have autoimmune disease and you would be putting a foreign body in your body.  Not the wisest choice.  While I never wanted the lap band, I did some reading on it, and the manufacturer's literature specifically stated not to get a lap band if you had a history or family history of autoimmune disease.  That said, the first surgeon I consulted with was more than willing to do a lap band on me as an "off-label" usage.  Also, there are many people on these boards with lupus and other autoimmune diseases who have had the lap band and had no issues what-so-ever.  Again, it's something to discuss with the doctors...first the rheumie, and then a surgeon.  You might be better off with the sleeve or RNY.  If you go for RNY, you won't be able to take NSAIDS or steroids.  Disclaimer on that statement, I was told for a short period of time with the use of proton-pump inhibitors, it would be okay.  The sleeve doesn't restrict your drugs.  I would also recommend staying away from the DS surgery.  There is a higher risk of kidney issues and you are already at risk for kidney issues due to the lupus (if you don't have kidney issues already).  Speaking of kidney, if a nephrologist is already part of your medical team, you would want to consult him/her about the surgery as well.  Actually, I would recommend consulting any specialist who is involved with your autoimmune issues about surgery.

I had RNY in May 2009.  Before surgery, I lost 70 pounds.  Since surgery I've lost 130-140-ish (I'm sort of stuck at the moment...and I would partially blame that on my lupus).  Best thing I could have done for myself.  Lately, I'm having issues with pain and fatigue...otherwise, I go to the gym religiously 5x/week, eat small portions, high protein, low carb, low fat, low calories, etc, etc, etc

I'm sure there is more I'm missing that I should mention, but I'm exhausted and not thinking well.  If you have questions, feel free to ask.
-Elli