1. LV 54 highway and Lv 53 large park.
2. Riot and military green.
3. A grey brown mace or axe for both.
4. Nothing for the later as it was slower than my scavenger and NOT bullet proof but bullet resistant (1-2 effective damages per bullet). Killed it in 2 waves by kitting it while my scout (684 DPS) fired at it. Note that given the resistance any weapon with high APS is probably more effective against this kind of guy, even more with high knockback. The former was bullet proof and came in a rush, lost my two guys in seconds.
I noticed no problem about kiting like some reported, maybe it was trying to attack it with melee then retreating, then I would understand it doesn't work.
My two cents about that:
First, resistances should never be 100%, Explosive resistance should be very low or inexistant given the limited supply, damage and the difficulty to hit a moving target. Melee and bullet resistances should be 50% base for RARES and then be altered with opposite values: 70% melee and 30% bullets, 90% melee and 10% bullets and so on. For UNIQUES the base could be 70%, caped around 95%. That would avoid the the situations where it cannot be killed by the present survivors.
I think there is 4 characteristics that are important: speed, damages, health and APS.
I prefer a system where any super being use a point like mechanism: they randomly 'spend' some points in each characteristic (let's say each with 4 levels), like 5 points for rares and 7 or 8 for uniques. So we can meet some high speed elite Z with good health but low APS and damage, or a high damage and good APS elite Z but very slow and with low health.
I think that simple system, if it can be used, would provide a nice balance. And probably limit the bad situations where they are unkillable or insanely strong.
Don't forget the knockback. At the moment it seems to exist only when there is damage, I think it should always work. Ok for the elite to not be knocked over by explosives but the knockback should be always effective. Maybe reduced to half.
Also I only know I killed a RARE elite because it's written on the box I was rewarded with, nowhere else I know. It would be nice to be clearer on that.