It sounds like things are working as designed.
1) Vera doesn't use a generic "on" command, it always uses levels. Even clicking "On" from the UI results in a message that essentially says "set to 100%." Altsteon takes that, translates it into the appropriate command, and sends it. I had a way around this, but it involved editing code or LUA files. I will have to look.
2) That's as designed. No Insteon setup repeats messages down the chain. Imagine if you had 2 device, A and B, and either could turn the other one. You turn on A, which turns o B, which turns on A, which turns on B...the firestorm might not end. Use a scene instead of controlling the switchlinc directly. Then the switchlinc and dimmer will be in sync.