I think these are relatively easy for prototype or hobbyist level soldering.
The WCSP-4 has only four balls - just glue it upside down to the PCB and solder on jumper wires with a fine-tipped iron. Easy-peasy.
The edges of the pads on the RSW, as pstuckey said, again mean that a fine-tipped iron could be used, this time with the chip glued solder-side down. Or do it dead bug like the above. That's probably easier.
Preparation (flux, tinning), patience, no coffee for two days and a binocular microscope are useful assets for these chips.
A hot plate would be another good method for either package, but a solder mask helps to allow the parts to auto-centre. I don't usually have that luxury myself, being a cheapskate hobbyist.
Seriously, these are not all that hard to do.