well IM not really sure what the question was in that.. But ill do my best to help you out..
A DoT(Damage over Time) heal - is actaully called a HoT (Heal over Time). Now In the warden spec its self i think theres only 5 single target heals..And those are
Healing current - Small castable heal that also leaves a HoT on your target
Healing Spray - Instant cast HoT
Deluge - Your big cast heal (bonus healing based on the amount of hots on your target)
soothing stream - A instant cast stackable HoT
Orbs of Stream - Castable Puts 3 stacks/counters on a ally and when hes struck it removes a stack and heals for a set amount
I checked all the roots/trees and i couldnt find anything about creeping remedy. so im kinda left out in the dark there..Now as for your planar essences They can proc off HoT's because as of right now each tick counts as a healing spell. I have one "you healing spells have a chance to heal your target for an additional 200HP/8s(this was a lvl 18 epic essence). ive seen this proc on a player off of my soothing streams.
Now the last thing i want to mention is your use of the word mitigate. this means to Lessen..So you dont mitigate heals thats bad...Tanks Mitigate Damage so they take less. Im assuming u meant to use the word more like this, How do HoTs (work, synergise, Act, Respond) with the target procs.
But if this didnt help at all..link me the creeping remedy and ill try it out if i can find one.