Assuming I want my mod talking to other mod APIs for additional recipes/power/options etc., is there a sure way to make sure my mod loads after those mods?

 

From the wiki I saw that you can specify dependencies via:

"required-after:ParentMod;required-after:ParentMod2;required-before:ChildMod"

 

But since they are specified as dependencies I assume if they are not present, my mod will simply not load up.

 

From what I've read I think I can just append a couple of leading "z"s to the mod id and hope that none of the mods which APIs my mod talks to has appended more "z"s but that seems unreliable and a somewhat hackish way to do it, which I would like to avoid if possible.

If you only need to deal with things like recipes and options that don't affect your mod's Items / Blocks directly during pre-initialization, then you can simply check if the mod is loaded in postInit and do what you need to do there. Use Loader.isModLoaded("modid") to check if a mod is loaded.

See

cpw.mods.fml.common.Loader#computeDependencies(String,Set,List,List)

for how to use dependency string.