Sorry for not getting back to you sooner.
First, let's disable the Devotion ability. Create a test character who's a normal druid with a normal animal companion - make him 20th level. You'll use that to look up information about the abilities that you want to replace.
The first step is to open the Develop menu, and make sure that "Enable Data File Debugging" is checked.
Now, switch to the Special tab on the animal companion, and right-click the Devotion ability. The bottom option is "Copy Unique Id (cAnimDevo) to clipboard - select that option.
Now for the editor. Switch to the race you're creating. At the top right, press the "Eval Scripts" button, and add a new Eval Script.
Leave the Phase at "First", but change the priority to "10000".
Now, in the "Script:" portion, add the following lines:
Code:
perform hero.childfound[cAnimComp].assign[Helper.SpcDisable]
perform hero.childfound[cAnimComp].assign[Helper.SpcReplace]
perform hero.childfound[cAnimComp].assign[Hide.Special]
Note that for the cAnimComp portion of those lines, I used the Id that I had copied. I do apologize that you'll just have to accept that those lines are the way to disable something - I can't think of a good example I can point you to where you could have learned that for yourself.
Now, to get Evasion to start at 2nd level, instead of 3rd. Unfortunately, we're going to need to create an odd fake for this.
In the editor, go to the "Ability" tab, and press the "New (Copy)" button. Find "Evasion (cAnimEvas)" in that list and select it. Now, at the top, enter a new Id for this copy. I'd use "cMGAnimEva" - my initials are MG, so by using that in all the custom content I create, I greatly reduce the chances that I and someone else will both pick the same Ids for two different things we create in the editor.
Back to the race. Press the Bootstraps button at the top right, and add a new bootstrap. Type in the Id you chose (or copy and paste the Id). Press the "Condition" button that's to the right of where you enter the Id. Leave the Phase as "First", and change the priority to 502. Now, enter the following code in the box labeled "tag expression":
What we've done is to set it up so that at level 2, this fake version is shown. Then, at level 3+, the normal version is shown. The idea is that to the user, it won't look as if anything changed about the Evasion ability between levels 2 and 3 - their companion got the ability at level 2, and kept it all the way to level 20.
Setting your own abilities to not kick in until some level or another is done the same way that we made the fake Evasion only kick in at level 2, with a bootstrap condition. Here's an example of level 5+, for your gaseous form ability:
Like the bootstrap condition for Evasion, you'll use First/502 as the phase and priority for this bootstrap condition.
I think that covers everything - how to disable the abilities you don't want, how to extend the range of levels over which you get one of the existing abilities, and how to keep the new abilities from showing up until a certain level.
Please ask if you don't understand any of that, or if you need more help.