Is there an ending for full metal panic? And which comes first, fumoffu или the секунда raid?

секунда Raid comes before Fumoffu :)
Fumoffu is like a bonus series with no real storyline, made purely for the lolz XD

I don't know about timeline wise, but in the real world, Fumoffu was released before The 2nd Raid. As for an ending, I only hope they do have a conclusive ending one day. That's why I hope TokyoPop continues putting out the FMP pop novels.