Ed, I can't address your router plate question but your question about bits is a very common one from someone who is just getting into routing. There are a couple of approaches that you can take. Some people buy a set of many different bits where the price per bit is low but, usually, the quality is not best although the bits will work. Then, when they find out what bits they use the most they then buy higher quality of those specific bits. There are probably some members of the Forum who took this approach who can better address their experience.
I chose to purchase bits one at a time as I needed them based on the project that I was doing at the time. Using my best guess as to how much I'd use the bit in the future I'd buy mid-level to higher end bits. Over the years I've gravitated to Whiteside bits. They aren't cheap but they are of excellent quality and can be resharpened a number of times. Once again, other members can comment about their experience with specific manufacturer's bits and which ones they like and which they stay away from. I hope this helps.
I chose to purchase bits one at a time as I needed them based on the project that I was doing at the time. Using my best guess as to how much I'd use the bit in the future I'd buy mid-level to higher end bits. Over the years I've gravitated to Whiteside bits. They aren't cheap but they are of excellent quality and can be resharpened a number of times. Once again, other members can comment about their experience with specific manufacturer's bits and which ones they like and which they stay away from. I hope this helps.