1) Actually it doesn't need to be a Static IP Address, as long as you are using the Access Key method to connect to the Server, and all your PCs have access to the internet, to look up the Access Key and obtain the current IP Address of the Server. It is actually recommended to use IP Address Reservation though, which is like a Static IP Address, but the address is assigned and maintained by the DHCP server on your network. A search of the forum for "IP Address Reservation" will find lots of info.
2) I've never seen that on my Client, but I only use a keyboard on it, not an IR Remote. Left and right keys skip video as expected, always. I would think this was an environment issue, not a MC issue, or there would have been many reports. Are you using an IR Remote? Any additional IR software? Is MC in focus when you try to skip forward or back?
3) The Client will save a Bookmark for any and all video, and restart from the same location, if the Client is set to Synchronise to the Server, and full Authentication is turned on. This is a well tested and discussed feature. It works. If you start watching on one Client, press Stop, then go to the other Client and play the same video, it will start from where you left off. But you do need to allow a little time for the first Client to synchronise the Bookmark tag back to the server, and the second Client may not pick up the Bookmark immediately, although it will if MC is restarted, or reconnected to the server.