Leprechaun
Its a CR 2 race, this means at most it has two levels before classes can start. But should this be turned into a progression, for example not getting all the Ability score bonuses till second level and some of the At wills being limited times per day.
Or should it be reduced down to a CR 1 or less by removing things like the Major Creation which is hardly a requirement to be one by Lore.
My idea for this PC is a Bard character, maybe a Druid if it fits the thematic feel of the Leprechaun more.
As for its magic ability the At Wills would be at a Reduced level to the PC so at lvl twenty maybe it would read as a level 10 or 15 then reduced by half for the DCs With a Static +5 Concentration bonus till lvl 10 and then be a +10 from there till 20.
http://www.d20pfsrd.com/bestiary/monster-listings/fey/leprechaun
Leprechaun
Every time I click on the link it says I am making to many requests at the same time, so this is a link since for some reason I cannot find the Edit Tab for the post above.
The reason the link above was screwing up was because you forgot the http:// at the beginning. Forgetting that tricks the forum into thinking you're linking to an in-forum address, but when it can't find the requested link it spits out an error.
Also the Edit button vanishes after one hour here.
No advice for the alterations at this time, but maybe I'll be able to get back to you later after work.