A topic from AEG's L5R CCG Rules forum, copied for Oracle of the Void from a copy of the forum saved in October 2015, so pages it didn't save are missing. Players' names are left out; the rules officials are named. Rulings are as they stood on these dates; later rulings, the rulebooks and the Rules Archive may differ.
A player, 10 January 2011
Starting a legacy deck to make use of some of the old cards I have (just for fun) and I can't seem to find one question - or I might be misreading - on playing experienced personalities. Can you play multiple experience levels of the same personality? For example, can I play Moto Chagatai exp, exp 2, and exp 3 all in the same deck? If so, does Overlaying work the same? (If I have a personality that is exp 4, can I overlay them on a non-exp version or does it have to be on the exp 3 version?)
Thanks, I tried a search, but my search-fu is weak today, it seems.
Roger Giner-Sorolla (rules official), 10 January 2011
Even if they are Unique, Experienced cards with the same title but different experience levels may be included in the same deck.
Likewise, more than three Experienced cards with the same title may be included in the same deck, as long as each Unique one, and each set of up to three non-Unique ones, has a different experience level.
And
During the Dynasty Phase, if a Personality is face-up in one of the active player's Provinces, it can overlay a less experienced Personality with the same title controlled by the active player.
where from less to more experienced the levels in Legacy go "Inexperienced < [Non-Experienced/basic] < Experienced < Experienced 2 < Experienced 3 ...[etc.]" So exp 3 can overlay exp 1 and so on.