I am a newbie also, but hope I can provide at least a direction to answering your question.  Some physical responses associated with telling a lie are increased heart rate, dilation of pupils, increased respiration, change in posture, and change in vocal patterns.  If someone were able to detect these minute changes in the person being questioned, that would not be an invasion into their mind using magic.  I would think that Supernatural Sense (YS 165) would cover these possibilities.  To give this temporary ability to someone, I looked at YS 265 Meneuvers and Contests and Conflicts.  Assume the person receiving the Supernatural Sense is going to allow it to happen (Resistance +0).  Maybe 2 shifts to give a -1 Refresh power.  5 Shifts to go from instant length of time to 15 minutes.  I come up with 7 shifts.  Minor comment though, during those 15 minutes the person receiving the Supernatural Sense aspect will be inundated with sensory overload as he/she is not used to the extra input, so normal talking may sound very loud, normal lighting may be extremely bright, etc. unless they have had this done to them several times before in which case they would be used to it.  Hope this helps, and I hope I am target with my numbers.

I like the idea of him having a sword of the Summer Knight, then somehow (insert major story line here) he is also given the opportunity to wield one of the Swords of the Cross, and he has to use powers from the Summer Court and the SotC in order to overcome some major evil thingy (maybe winter court evilness coupled with a mortal sorcerer raising demons or forcing fae to do his will).  Perhaps the two swords merge in to one for a brief period of time, if there are no conflicts and he adheres to both tenets, and should one tenet be broken, he will not be strong enough to defeat the evil.

Interesting idea...maybe the shaman would know the true name of the spirit of hunger that hunts aka panther spirit.

For taking it out mentally, 3 (to overcome 2 mental base) + 2 mild + 4 medium + 6 severe + 8 extreme, um 23...
As for the overcome Mediocre conviction, why 5? 
Different possibility, apply 6 shifts to get 20 skill points and 6 refresh, or 7 shifts for 25 skill points and 7 refresh, or 8 shifts etc.?

It is for an NPC, I am just trying to enhance my understanding of how the different magic things work, because half of what I may do one of my PCs may turn around and ask "How did you do that?"  and I want to be able to give a metagame answer that makes sense in case they want to try something similar in the future.

This is close enough to a panther.  If we use Conjuration skill, my home approach to this is +7 shifts for medium animate, then 1 shift for every skill and 2 shifts per refresh point, so


High Concept: Mountain Lion
Other:
Silent Killer
Scaredy Cat

Skills:

Superb: Stealth,                              1 x 5 shifts       
Great: Athletics, Fists,                      2 x 4 shifts
Good: Endurance, Intimidate,             2 x 3 shifts
Fair: Alertness, Survival,                   2 x 2 shifts
Average: Discipline, Might, Presence,  3 x 1 shift

Powers:

Claws [-1]                                      2 x 1 shift
Echoes of the Beast [-1]                   2 x 1 shift
Inhuman Strength [-2]                      2 x 2 shifts
Inhuman Speed [-2]                         2 x 2 shifts

Total Refresh: -6

Stress:

Mental: OO
Physical: OOOO
Social: OOO
Armor: 0.

So 45 shifts to summon the "panther" using conjuration.  If we add another 2 shifts, we would get a handful, 4 shifts would give us maybe a dozen, 6 shifts would give us enough to fill central park if I remember correctly.  So call it 49 shifts to summon 12 panthers, again using my homegrown method to calculate the cost based on what I remember from conjuration and what I came up with earlier.  Hmmm...add in 12 shifts for lasting a mortal lifetime?  Something similar could be done for the apes, snakes, and birds.  Maybe 244 shifts as an approximation to get 1 dozen panthers, 1 dozen apes, 2-4 dozen snakes, and probably 4 dozen birds. 

Maybe the transformation is done first, then the conjuration.   So, how would the transformation work?  I really want something permanent, not an illusion at this point.  However, now that you have my curiousity aroused, what would it be for an illusion? 

I would think it would be two different wards.  Add 2 shifts for a condition to trigger the wall ward.  Given the size you are talking about, it would probably need 2 more shifts to cover that much area as well.  Oh, and don't forget to add more shifts to make the ward last longer than until next sunrise, even though it hasn't been triggered, the construct needs to last for a while.