Well, for yellow mold I just basically used the entry for the Doomspore hazard, but I did ignore the attack only working on bloodied creatures. Obviously the description changes a bit, but not much.
Brown Mold I would just up the level of the yellow mold a couple of levels, and change the ongoing 5 poison to ongoing 5 cold, and remove the stipulation that it can only work once per 24 hours. Remember to increase the DCs to identify and avoid triggering it by a couple of points. I also required a DC20 perception check to see it in the first place.
Green Slime is a little bit nastier if you are going to make it approximately similar to the old fashioned kind. Something like this should be fun, I think:
Green Slime Level 7 Obstacle
Hazard XP 300
Found in damp caves and other similar areas green slime is a nasty plant-like growth which feeds on any kind of organic material, turning it into more green slime.
Hazard: A single patch of green slime fills one or more squares. The square is considered difficult terrain and a DC19 Athletics check is required to avoid falling prone while moving through the square.
Perception: The slime is noticed automatically, but see additional.
Additional Skill: Nature DC24 The character identifies the patch as green slime
Trigger: The green slime attacks whenever a character begins his or her turn in its square.
Attack
Opportunity Action Melee 1
Target: Creature in the square
Attack: +12 vs AC
Hit: 2d10 acid damage and 10 ongoing acid damage (save ends).
Special: The character gains a +1 to save vs the ongoing damage for each point of fire damage taken since the character made their last saving throw attempt against the slime.
Additional Effect: Any creature which dies while green slime is doing ongoing damage to it dissolves and becomes a new patch of green slime at the end of the 5th round since the creature died. Once this happens the creature's body is destroyed.
Countermeasures: Each square of green slime can be destroyed by doing 50 points of fire, acid, or cold damage to it. Green slime has defenses 20, vulnerable 5 fire and acid, resist 5 cold.
Upgrade to Elite (600XP)
Increase Nature DCs, attack rolls, and defenses by 2
Increase size to Large
Sound good?