Your question about the electric brakes has already been answered above.
Regarding your secondary questions on Bal-X chocks and Lynx levelers, I would recommend do both. Try this accessory for your Lynx levelers:
They lock-in to the Lynx leveling pads and give you more roll-away prevention than the cheap $3 yellow plastic chocks.
With regard to the Bal-X chocks, they do provide great friction brake effect on your tandem wheels, (like an old friction brake on a conestoga wagon--watch an old western or Little House on the Prairie when the wagon driver sets the brake when stopping the wagon). But more importantly, in such a long TT as the 32BHDS, the Bal-X helps to reduce some of the "bounce" you will experience throughout the entire trailer when someone walks or jumps at the other end of your TT. It essentially takes two separate round wheels and converts/locks them into an oval with flat sides with less rolling/rocking of the wheels. Remember, your tandem axles/wheels are set on leaf springs and they are designed to have bounce, which allows for some mini-rolling during inside human movement. Engineering-wise, the best way to eliminate long TT bounce would be to add a middle pair of scissor jacks just forward of the front axle (neutralizing the axle leaf springs). I have not had to make this Mod, since DW and I are very happy with how much the simple addition of the Bal-X chocks has satisfactorally neutralized most of our 32BHDS bounce. The Bal-X are presently on sale for $34.99 at adventurerv.net.
I apply my Bal-X deluxe chocks and regular wheel chocks prior to unhooking from the truck. Once I am all set-up (level, corner stabilizer jacks, slides, etc.), I go around and do a final gentle crank on the Bal-X chocks and the corner stabilizers, since they can loosen slightly after set-up.
Hope this helps.