Rebel wrote:2. Rating lists tend to operate in pools of similar strength. Kind of elo incest. What happens to the elo of high rated engines if they placed into a pool of (much) weaker engines, would their elo drop?
I would say: impossible to answer! The rating of an engine A in pool P1 is completely unrelated to the rating of the same engine A in pool P2. So you can't say whether A's rating "drops". A has a rating relative to pool P1 and another rating relative to P2. There is nothing that connects P1 and P2.
Even if P2 is a subset of P1 that only contains A and "some weaker engines" then P2 is still a different pool. I would never attempt to compare P1 ratings to P2 ratings. Many people actually do things like that, e.g. they compare CCRL 40/4 and CCRL 40/40 ratings; I would never have done that ...
I think there are some people who might believe that an ELO rating is something like an absolute, physical property of a chess player (or engine). It simply isn't. An ELO rating is a number that can only be interpreted in a very limited context, and that context is the set of other ELO ratings in the same rating pool. That rating in relation to those other ratings tells us something about the expected outcome of games against the owners of the other ratings, nothing more. "ELO 3200" of a chess engine within a computer chess rating list does not mean an expected outcome of about 92% against a "2800 ELO" human GM, it means nothing like that, simply because engine and human GM have their ratings from different pools. One may argue that computer chess ratings are "meant" to resemble ratings of human chess players, and perhaps some engine ratings were "likely" comparable to human ratings, but in fact nothing tells us how far both pools are away from each other, unless you include a significant number of human players with a significant number of games into the engine pool (and even then you run into trouble since human playing strenght changes over time in contrast to that of engines), or vice versa.
For the same reason, a strong engine that is put into a pool with weaker engines simply gets a different rating there that can't be compared to those in other pools. It does not "drop" or "rise".