Can i play fe. Palace of the Breaking Dawn with Kobi Sensei?
http://rules.alderac.com/cr_for_20f/#sensei
A player may only start with a Sensei that is “All Clans” or has his or her Stronghold’s Clan in the restriction list.
All Clans Sensei and Unaligned Strongholds
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.
Can i play fe. Palace of the Breaking Dawn with Kobi Sensei?
Yes, as it says "All Clans".