I believe you can only participate in one league with one email address and "name". If you have multiple email addresses I believe you can compete with each email address and "name". I have entered "twice" with different emails and "names". I believe others have entered for each spouse and each kid, in the same league.
My "strategy" has been to pick the musher or mushers that I believe will outperform the other mushers in their price pool -- such as the best of the $4,000 mushers, or the best of the $2,500 mushers, etc., in my opinion. Their scoring system awards points for # of dogs into each check point, and position of the musher into the check point, etc. -- so my "strategy" is to select mushers with a history of finishing the race while keeping their dogs moving on down the trail, healthy, happy and hopefully rapidly.
You must spend up to $27,000 fantasy dollars on exactly 7 mushers -- so money management is a major factor of the strategy.
It's all for free and for fun -- so it's "fun" to see how you are doing among the Iditabuds whose forum names you have become familiar with. The fantasy formulas are dynamic so things change throughout the race and even through the banquet after the race as points are awarded for awards given at the banquet.