The manual is wrong about the learning; You aren't limited to four buttons; You can learn on almost any button. It sounds like the website was misleading about learning. You don't have nearly enough learning memory to support several devices with learning as your primary method. You MIGHT have enough for several built in devices with learning covering the exceptions.

Of course you can use JP1 to get complete support for all those devices easily with your 8910. I think the 8810 is better (more flexible JP1 support and doesn't have that stupid ring for arrow keys).

I know some Replay remotes can be customized with JP1 to do everything you mentioned. I'm not an expert on Replay remotes, so I couldn't say whether all Replay remotes can be (My guess would be yes).