Is/was ESSO 2-T the same thing as regular 2-cycle oil?
I'd guess so, yes. Esso is just the name of an oil company - part of ExxonMobil now. Esso comes from 'S' 'O', which comes from Standard Oil. Outside of America, Esso is to us what Exxon is to you. I have no reason to believe that Esso 2T oil was anything different (in general terms) from any similar 2T oil.
One difference may be whether the oil they recommend is prediluted or not.