NO NO and NO. Elite Plus on one does not mean much on the other besides lounge access and maybe if you get lucky an upgrade on an overbooked flight (based on priority).

FB Silver Elite gets 5 kgs extra, Gold Elite gets 10 kgs extra while Platinum gets 20 kgs extra. This is only applicable on its own AF/KLM flights. Your Platinum status on Delta does NOT earn you such privillege. Each airline within SkyTeam definitely has to offer certain benefits for its own program, this is very common. This works the same on FB Platinum or Elite who do not get free domestic upgrades when they fly Delta within the US....they could have argued why their elite plus does not give them this benefits on Delta...

Regarding the 32 lbs and 32 kg at IAD, I am very surprised how that could have happened as all scale at all US airports (as far as I know) are measured in LB, not KG. This mistake should not have happened so easily. Especially, you pack the bag yourself (or not), how could you not know how much weight it is (at least estimatation). 30 kgs is a heavy bag, you could feel the difference between 30 kg or 30 lb when you pull it into the checkin counter. As lb and kg is different by 2.2:1 as we all know.