No, no need for the snubber washers on aftermarket style bushes.
Correct, but do replace the snubber washer with a normal washer so the total stack-of-washers thickness remains the same and you don't crush/bend the chassis pickup point as you tighten the bolts.
I also find it useful to buy the same large castor washers for the rear upper mount as well.. Saves a huge amount of time with refitting as you don't need to mess with getting the small washers to fit which can be really annoying.
If you use new washers then a good trick is to super-glue them together so you don't need to fit 'em separately.
Bye, Arno.