The ESB MKII suits and helmets are very real. I have said it for years and will continue to do so. There is no doubt in my mind that at least two suits seen in ESB are definately not the same as an ANH suit and closely resemble an ROTJ suit. I am sure hard evidence will present itself in the future...it's just a matter of time. But, you are right - only a couple of suits probably made and that is why there is hardly any reference material available.

Back to your question - all abdomen plates are solid one piece sections - no splits.

Yes, it would have been a huge amount of work to make new suits for ESB and I have no doubt it was. So much so that they didn't manage to get the suits finished in time for fiilming and was forced to use left over suits from ANH that were wrecked. We can see just how badly the suits were with parts missing and held together with duct tape - something I don't think was intentional if they had the choice.

I believe that all new ABS armour and helmets were made but not finished in time and that is why we only see two on screen. There is no doubt about John Mollo's notes and new costumes had been discussed for the the production of ESB. Also, the Getty photos of the two troopers outside Harrod's (or wherever) in London dated 1980 and the ESB promo poster witht he two different troopers and Vader also dated 1980. The evidence is there in plain view.