Do you think the block is cracked? If not, can anyone tell me what
potential areas I should look at to find the contamination point
(water leak to block / oil)?

First step, pull the plugs and examine them to see which cylinder(s) is
leaking.
The next step, assuming that you find a suspicious cylinder, is to pull that
head, examine for cracks, and check/change the gasket. A new water leak may
be almost invisible on the gasket, so look closely, especially around the
problem cylinders, and hopefully you'll be able to check both sides of it.
Someone else will have to give you furthur diagnostic advice pending your
results.