I would have some questions of my own:
1. How many keepers per team? The more there are, the worse it is for you.
2. Are you taking over an existing team? If so, how do those keepers look?
3. How long do you get to keep a player?
As for your questions:
1. Yes, if you are taking over a really bad team or if a lot of keepers are being kept. No, just from a fantasy sense. There aren't that many differences. I will post a link at the bottom of the page for some keeper points.
2. It is more of a disadvantage coming in late but, depending on the rules and answers to the questions above, it might not be too bad.
Here's the link:
http://www.fantasybaseballcafe.com/foru ... hp?t=27839