Level 4, or 5?

[HyperMissingno]

So I'm planning a boss for my level 2 party...and I'm not sure if I should make them level 4 or 5. The boss is an Illusionist Kobold Wizard with Evocation and Abjuration as opposition schools for specifics...I should probably spoiler that in case one of my players pokes around.

Ze Wizard:

AC 18, touch 13, flat-footed 16 (+4 armor, +2 Dex, +1 natural, +1 size)
hp 20 25 (4d6+4)
Fort +2, Ref +3, Will +4

Speed 30 ft.
Melee: Quarterstaff +0 (d4-2)
Ranged Touch Attacks: +5
Wizard Spells Prepared (CL 4th, Con +7) (CL 5th, Con +8)
3rd: Illusion of Hell Silent Blindness Twice
2nd: Invisibly, Invisibility, Minor Image, Blindness
1st: Mage Armor, Sleep, Mount, Color Spray, Vanish
0 (at will): Detect Magic, Read Magic, Prestidigitation, Acid Splash, Ghost Sound

Str 6, Dex 15, Con 12, Int 16, Wis 10, Cha 12
Base Atk +2; CMB -1; CMD 10
Feats Eschew Materials, Scribe Scroll, Craft Wondrous Item, Silent Spell Secret Signs

Skills SoH +6, Arc/Scraf +10 Dun +8, K other 6
Languages Common, Draconic, Dwarven
Special Traits May cast one spell with Silent Spell added for free.

The spells he can pull at once include Acid Dart, Magic Missile (he is angry that nobody told him of that when he first started studying magic), and if he's level 5, Suggestion.

In addition he will have two lackeys guarding him.

Ze Lackies:

AC 17, touch 13, flat-footed 15 (+3 armor, +2 Dex, +1 natural, +1 size)
hp 19 (2d10+4)
Fort +4, Ref +2, Will +1 (+3 against fear)
Weaknesses light sensitivity

Speed 30 ft.
Melee Kukri +5 (1d4+2+1d6 18-20)
Masterwork Sap +6 (1d4+2+1d6)

Str 10(14), Dex 15, Con 13, Int 10, Wis 12, Cha 8
Base Atk +2; CMB +1; CMD 13
Feats Weapon Finesse, Mobility, Precise Strike
Skills Perception +5, Stealth +8; Racial Modifiers +2 Craft (trapmaking), +2 Perception, +2 Profession (miner)
Languages Draconic
SQ crafty

These guys are swarm fighters. They get Mobility as a feat at the first level and a teamwork feat at the second level.

The arena looks like this, do pardon the not safe for work language on the right, I kinda use it to keep track of secret stuff.

Prebattle Spells:

Our wizard is placing Bull's Strength on his lackeys, invisibility on himself, and minor image to make a hostage. There's bell traps all over the place and several mooks have signal whistles as a note.

As for my players...

Ze Bardadin:

AC 16/19, touch 13/16, flat-footed 13/16 (+3 armor, +3 Dex, +3 Deflection)
hp 17 (1d8+2 1d10+1)
Fort +4, Ref +5, Will +3 (7 if charm or compulsion)

Speed 30 ft.
Melee: Scimitar +4/+2 (1d6+3) Kukri +2 (1d4+1)
Special Attacks: Bardic Performance/Battle Dance +1 (7 rounds/day)
Smite Evil: (1/day)
Bardic Spells (CL 1st, Con +4)
0 - Detect Magic, Prestidigitation, Light, Ghost Sound
1 (2/day) - Dazzling Blade, Saving Finale

Str 16, Dex 16, Con 14, Int 12, Wis 9, Cha 17
Base Atk +1; CMB +4; CMD 16
Feats: Two Weapon Fighting

Racial Traits: Cat's Luck, Clever Cat, Climber, Low-Light Vision

Ze Cleric:

AC 19, touch 11, flat-footed 18 (+6 armor, +1 Dex, +2 shield)
hp 22 (2d8+7)
Fort +5/7, Ref +1/3, Will +6/8

Speed 20 ft.
Melee: Warhammer/Battleaxe +3 (1d8+2)
Ranged: Magic Stone? +3 (1d6+3)
Special attacks: Channel energy (1d6) (3/day)
Spells: Unknown at this point, has prepared Bless, Compel Hostility, and Magic Stone so far

Str 15, Dex 13, Con 15, Int 10, Wis 17, Cha 10
Base Atk +1; CMB +3; CMD 14
Feats: Toughness

Racial Traits: Defensive Training, Hardy, Stable, Greed, Hatred, Darkvision, Weapon Familiarity

Ze Sorcerer:

AC 12, touch 12, flat-footed 10 (+2 Dex)
hp 15 (1d6+2)
Fort +2, Ref +2, Will +3, +5 if Charm or Compulsion

Speed 30 ft.
Ranged: Spells +3
Special Attacks: Freezing Touch (Touch attack, staggered 1 round)
Smite Evil: (1/day)
Sorcerer Spells (CL 2nd, Con +7/10)
0th – detect magic, breeze, ray of frost, prestidigitation
1st (5/day) – create ice, freezing hands, snowball

Str 9, Dex 15, Con 14, Int 14, Wis 10, Cha 19
Base Atk +1; CMB +0; CMD 12
Feats: Elemental Focus (Ice), Greater Elemental Focus (Ice)

Racial Traits: Bonus Feat, Skilled

Note, she's using a homebrewed bloodline and we houseruled that sorcerers get their bloodline spells on even levels.

Ze Witch:

AC 17, touch 13, flat-footed 14 (+3 Dex, +4 armor)
hp 15 (1d6+2)
Fort +3, Ref +2, Will +5/7

Speed 30 ft.
Melee: Hair +5 (d4+4, Grab)
Ranged: Crossbow +4 (1d8)
Special Attacks: Constrict (Hair)
Witch Spells Prepared (CL 2nd, Con +6)
Not sure what she will bring but she tends to prepare Cure Light Wounds and Mage Armor, can prepare divine favor due to patron and can pull shield out with her ring.

Str 12, Dex 16, Con 15, Int 18, Wis 10, Cha 9
Base Atk +1; CMB +2, +5 with hair; CMD 16, 19 with hair
Feats: Defensive Combat Training

Racial Traits: Elven Immunities, Dual Minded, Keen Senses, Low-Light Vision, Elf Blood, Multitalented

White Haired Bonded Witch

So with what I got...should I make the boss level 4 and go easy on the gas, or should I go full throttle and make him level 5?

[My Self]

Maybe 4, and toss in an extra minion. 5th level gives you a bunch of nice new tools that are perhaps over the top.

If you really wanted to hurt them, Protection from Arrows + Fly at 5th level.

[HyperMissingno]

...I knew I was forgetting something! We play with Hero Points and everyone in the party has 2 points each, so they all have a button they can slam in case of dire emergencies.