I put all the original stuff here. That which is highlighted in blue (ooc tags) are things I'm suggesting to drop or is the original in case of alterations.
In all forms
-Change Shape: multiple forms, humanoid, animal, and hybrid
--move action for natural lycans, or standard for afflicted plus needing to make checks.
-Lycanthropic Empathy: Felines
-Ability score boost: +2 wis, -2 cha
-Scent
-Low light vision
-Special Attacks, Qualities, and Abilities of base creature usable in all forms
-Gain Shapechanger subtype
In Animal Form
-Ability score boost: +2 str and con
-Use the better of creature or animal ability scores
-Curse of Lycanthropy
- Add +2 to nat armor (improves existing, if applicable)
-DR 5/silver DR10/silver for natural, DR 5/silver for afflicted
-Gains all special attacks, qualities, and abilities of base animal
Side by side, the base animals
Note, size modifiers are already accounted for in the following ab score modifiers (-4 str for margay, +4 str for tiger)
trait margay jaguar cougar tiger
size sml med med lrg
spd 40 40 50 40
clmb 30 20 - -
swim - 20 - -
str 2 8 6 12
dex 6 6 8 4
con 4 4 4 6
int -8 -8 -8 -8
wis 2 2 2 2
cha -4 -4 -4 -4
ac 0 2 2 3
bite 1d4 1d6 1d6 2d6*
claw 1d3 1d4 1d4 1d8*
pounce + + + +
rake + + + +
LLV sup + + +
acro 8 8(bal) 4 4
clmb 4 - - -
stealth 4 4/8 4/12 4/8
perc 4 - - -
swim - 4 - -
*Interestingly, in 3.x tigers achieved this damage via feats, while in Pathfinder, those feats were traded away but the damage left unchanged
These were all built on the ability score bonuses of +8,+6,+4,+2,-4,-8
Normally, the ability score stats are taken straight from the monster stat block unaltered, but those rules are intended for npcs only, and Pathfinder is even less accommodating than 3.x in terms of writing npc info to be usable for pcs, so I went with ability score modifiers as that makes more sense given that PC scores are built differently than for npcs.