I tend to agree with your (2) choice of Afren and Lukman. That combination would own a big chunk of the GOG deep and ultradeep. A 1/1 swap would only work if both entities had the same number of OS. Thus, SEO may have to retire a chunk of his personal shares for other consideration, .... so that the share counts are even. I would love to own Afren shares, knowing they own ERHE's rights.
The wildcard is China. They would probably only be considered on a large buyout.