IEI E8s eh? Can't say that I have.Plenty of EIE 8s, loads even, my aunt is one. No IEI 8s yet. I mean it could happen. I suppose there isn't anything too fundamentally conflicting about such a typing. IEIs tend to be a good deal more laid back than most 8s.
Fwiw I wouldn't try to use enneagram to justify a socionics typing. If your a driven motivated individual, you're a driven motivated indivudal. Don't ignore such information when considering your socionics type simply because your enneagram type covers it. Both theories attempt to be all inclusive in a way so dividing yourself to fit them is counter productive.