No, Dextron II and Type II transmission fluid is not the same. I learned this the hard way. I went to my local Jiffy Lube center and asked that same question, and of course they said yes as I wanted to do a transmission fluid flush (remove all old fluid and add new). Well after they were done I took my car and noticed that my transmission was shifting harder. I immediatley called my friend's friend, who by the way is a Lexus master mechanic and asked him about this, and he suggested to immediatley change out the fluid, as the fluid recommended by Lexus is a synthetic type fluid, Type II, where as the Dextron II is not. This can harm the transmission in the long run. Had to buy 16 quarts of Type IV, replacement for Type II, to have the whole transmission reflushed again. After that, my transmission was back to normal.
As for your coolant, in your owners manual says to use a good brand of ethylene-glycol, more than 50% of ethylene-glycol, but no more than 70% is recommended. But to be on the safe side, just buy the exact type from your local Toyota dealer as it is cheaper than the Lexus dealer.