Re: similar looking aircraft
Thanks to the laws of aerodynamics and materials science, there are only so many ways you can lay out an aircraft performing any given role.
Up to a point, but there's a question of HOW similar the Chinese version is. Rafale, Gripen, Typhoon are all somewhat similar designs, but I don't think I'd conclude that they were the product of espionage, whereas some aircraft designs are so similar that you have to conclude that they are copies.
Mind you, when it comes to keeping up with the military Joneses, the Chinese have a long way to go before they overshadow my favourite modern aircraft, the Iranian Q313 "stealth fighter"......