I've been searching the entire web to get a proper ST2 configuration to work with a Play! project (version 2.1)
I finally ended up to this configuration steps (greatly inspired from http://engineering.panaxiom.co.uk/post/34631917299/sublime-text-2-with-sbt-and-play-2) :
Added ensime plugin in project/plugins.sbt :
addSbtPlugin("org.ensime" % "ensime-sbt-cmd" % "0.1.1")
Generated ensime file project from play console with :
ensime generate
Installed sublime-ensime package for ST2 from Package Control :Install Package
Installed the ensime server ensime_2.10.0-0.9.8.9 and extracted files in ST2/Packages/Ensime/server folder
I also installed SublimeJava plugin for basic java code support and play2-sublimetext2 plugin for play specific syntax highlighting and snippets.
With all this configuration setup, I get two critical issues for application and third party lib
So there must be a way for cleaning up this, but I can't find how.... Please note that I write code in Java for Play, not Scala, but that shouldn't be a problem since it's jars paths in my .ensime file.
Thanks by advance to those who can help me.
This plugin is currently abandoned, so unless you or someone you know wants to take over its maintenance, nothing is going to get fixed. If you check out the project's issues page, there are currently two open issues for the features you mentioned: autocompletion (from Nov. 2013) and auto imports for Java (Nov. 2014). Neither one has any replies from the project devs, or anyone else, for that matter. Even the project's website is gone.
So, unless you can fix these issues yourself, it looks like you're out of luck. Sorry!