This is the text from the rule book for all the powers being discussed and a few comments. Any mistakes are my own caused by burnout due to work.
from pg. 79:
Crane Stance Chi: 1/ Shots: 1
If the opponet attempting to hit you has a Perception rating lower than your Agility rating, your Dodge increases by 5. Using Crans Stance is a defensive action. Prerequisite: none, Path: Wing of the Crane
The Fox's Retreat Chi: 1/Shots: 1
Add +5 to your Dodge value. Counts as a defensive action. Prerequisite: None, Path: Eyes of the Fox.
from pg. 85:
Willow Step Chi: 1 / Shots: 0
Your Dodge Value increases by 2 for the duration of the shot. Prerequisite, none, Path: Walk of a Thousand Steps
from pg. 86:
Intergration of the Clouds Chi: 1 / Shots: 0
Combine the use of two fu powers into one action affected powers must share a word in their titles (such as "Fox" or "Fire"). Fu powers with contradictory conditions, may not be combined. Pay chi cost for both, but only the highest shot cost. Prerequisite: Torrent of Furry
The problems and things to rember:
1.) Willow Step is not considered a defensive action, according to its' description. (If Willow Step was considered a defensive action, you couldn't combine it with an Active Dodge.) You can only make one defensive action against an attack. The defensive action is only good for that one opponet's attack.
2.) The rules don't clearly forbid the use of multiple fu powers in a shot. Emphasis on the word clearly. Well this is multiple actions too.
3.) Willow Step has a 0 Shots cost. (This is the big issue. If you start examing the 0 shot powers you'll see some of the problems they can give or advantages if you don't think they are a problem.)
4.) Note, that according to the FAQ for the game if the character was a Karata Cop his +2 AV bonus only goes to Active Dodges. So if he were to just Willow Step and nothing else he would only get the +2 bonus willow step gives. If he were using Willow Step with an Active Doge, Crane Stance, or The Fox's Retreat he would get a +7 to dodge. If the GM ruled that he could use Willow Stance with the Fox's Reterat or with Crane Stance that wold be a +9! 7.) The Scrappy Kid and the Uber-Kid, from Seed of the New Flesh, get a +2 to Dodge as their per their unique schtick when dodging with Martial Arts, also. So do be aware of this.
5.) Intergration of the Clouds combines the 2 actions in to one action. Something you don't need to do in this case.
If you are going to let a player use Willow Stance with Crane Stance or the Fox's Retreat, don't forget that doing that costs Chi, that could be needed latter on, and the character gave up taking another fu power. Another question is why do you need to do it if you have a high enough Av in the skill you are going to doge with? Is it truely worth it? You need a high Agility for Crane to work, only a few types have this.
Lets look at a starting Old Master has a Martial Arts AV of 16. That becomes:
16 with just a passive dodge
18 with Willow Step
21 with an Active Dodge
23 with Willow Step and Active Dodge, or Crane Stance, or The Fox's Retreat.
25 with Willow combined with Crane and the Fox's Retreat.
Do you really need the 25 Av? Is it going to make much of a diffrence? Is the cost worth the benefit.
For a Karate Cop the numbers are:
14 with just a passive dodge
16 with Willow Step
19 with an Active Dodge
21 with Willow Step and Active Dodge, or Crane Stance, or The Fox's Retreat.
23 with Willow Step combined with Crane Stancea or combined with The Fox's Retreat.
Do you really need the 23 AV? Is it going to make much of a diffrence? Is the cost worth the benefit. Also, the Karata cop does start with no Fu Powers and had to use hard earned experience to get those Schticks.
If you google +"Willow Step" +"Fox's Retreat" you'll get a bunch of hits in which this issue was discussed. Till an official answer exists, I'd say let the GM rule how to handle it.