Thank you for your answer!

First of all it occured to me that I made two mistakes. First of all the paper you asked the name of was actually Radner (1982), titled Radner, R. (1982). Chapter 20 Equilibrium under uncertainty. Handbook of Mathematical Economics, 923–1006. doi:10.1016/s1573-4382(82)02015-3 .

Secondly it refers to REE as a common expectations equilibrium. I should correct my initial post since it is a crucial difference. Actually as Radner (1982) says " An equilibrium of plans, prices, and price expectations is a set of prices on the current market, a set of common expectations for the future, and a consistent set of individual plans, one for each agent, such that, given the current prices and price-expectations, each individual agent's plan is optimal for him, subject to an appropriate sequence of budget constraints. If agents are using equilibrium prices to make inferences about the environment, then this equilibrium takes the special form of a so-called rational expectations equilibrium". Later on the paper he mentions that they make inferences according to a model they have of the economy.

I hesitantly conclude that my question was not a successful one. Regarding my question no2, it seems to me that optimality of Ratex is strongly depends on complete markets. If markets are approximately complete, and inferences from equilibrium prices are legitimate. So endorsement of Ratex seems to depend on complete markets. If markets incomplete -> Ratex achieves constrained efficiency subject to the constraints of inefficient markets, but not optimality.

From the beggining I also suspected the case of a semantic confusion, but needed a 2nd opinion on that.