Be prepared for anything that can come from LPI exams and Linux+, sorry RHCSA is no use with them at this time. I do not think it is the best way to gauge a candidate's experience with Linux but you should know all the basic stuff and be prepared to dive in for detailed answers. And be prepared to answer outdated technology used in the older versions of Linux which still in large of their customers would use such as iptable. I can almost guarantee they will ask you about boot sequence, TOP, netstat, and other tools (check LPIC engineer exams) for troubleshooting hardware resources at some points during the interviews. They want to know if you have knowledge of using those tools to troubleshoot server problems, make sure you know just about all the options for each of those commands. They will also ask you questions related to how those tools display information.