[Recommended settings for PCL filament?]

PCL has a very low Tg.  You might be able to print in the 65-85oC range. 

[What's the point of ABS?]

ABS has really good cold impact strength.  It's also very easy to print, more forgiving than PLA.  If I could only choose those between PLA and ABS I would take ABS.  However as Smithy stated above ASA is superior to both of those especailly for a part that will be outside or see UV.

[Trying to find a solution to printing with PC and support]

The trick to a breakaway support with PC is getting the goldilocks adhesion to the material and the build surface.  In my experience a PPE/PS alloy with a  Tg matching the PC and a MFI of 7-9 g/10min will work nicely.  PVA not compatible.  The only soluble support that I know of that can go that high a temp is locked up in IP and tremendously expensive for the "maker" market.