No need for leaded gas. The benefit of it is for older engines, with softer valve seats. The lead additive in the fuel provides a "cushion" if you will. On a 2 stroke, no matter the age, the lead is absolutely worthless, as 2 strokes don't have valves.
Run standard 87. On the older motors, higher octane won't get you anything, and the factory often recommends against such. With this ethanol crap we are getting, a regular usage of Stabil for ethanol (blue stuff, I believe) is great, as the ethanol just loves to get every molecule of water possible into your fuel. Furthermore, it eats away at the fuel hoses, as in 1975, Evinrude had no clue that fuel mixed with ethanol would be run in it, so provisions to make ethanol impervious hoses were nonexistent. If you're real concerned about it, a fuel/water separator would be a good investment, but I don't run one on any of my smaller motors. If I had a newer (read costlier, and also read less durable) motor, I would certainly be running one, but the old twin cylinder J/E's are simple and bulletproof enough that it doesn't affect them near as much as a new one. Plus, for what they cost, it just isn't a worthy investment, IMHO.