I think the OS 91 four stroke was a perfect match for my plane, so, I am biased and would choose option 1.
For me the only other possibility out of the four choices would be the GMS 76. I use the same 15% fuel in everything so the only "bad" thing about having a two stroke is the sound. I have an ASP two stroke on my Uproar 60. I like the engine a lot but do not like the sound that comes out of it.