The sim profile is pretty much the same for an SO as for an FO so if you were gonna do it for the DEFO slot I'd probably do it for the DESO slot as well.
I will agree with your reasoning on why you are getting SO interviews now as opposed to FO ones. THere are suddenly a bunch of freighter guys jamming up the system on the -400 and they are reallocating some aircraft out of NA due to the impending depression.
As for whether to come or not, that depends, can you find a decent job in the states right now?(Unless you are at FEDEX, UPS, SWA, MAYBE JetBlue, this job even as an SO is better and more secure than where you are at)
If you come to HK as an SO, after approximately 18 months you can be on a course to go on a base as a freighter FO, assuming of course that ,eet the requirements(if you were interviewing for an FO slot you do) and are assessed suitable.