well, here is what I have done in the end. Hope this is useful to someone else
Following this tutorial I've created maven directory structure for full Java EE 7 project (used java ee7 archetypes instead ee5 where applicable).
In root pom.xml I've added
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.1</version>
<configuration>
<source>1.7</source>
<target>1.7</target>
</configuration>
</plugin>
</plugins>
</build>
so all modules will depend on java7.
I've copied this to git root folder, added .gitignore file for eclipse files.
In Eclipse, I've used import maven project. After that, right-click root project (eclipse will create multiple projects) folder and Team > Share Project > local git.
I guess only thing remaining for other devs beside import maven project after initial git pull (outside eclipse), is to configure java ee application server (Window > Preferences > Servers > Runtime Environments)