do construct2 exported games work with the new cocoon service? and if yes, what export method should i choose? i had no luck with normal html5 export or cordova export.
Cordova exporter BUT I recommend to remove the config.xml provided by default by the exporter. Let the cloud compiler to generate a default one and, if you need plugins, install them using the wizard in the project settings.
and for the plugins, i saw that the new cocoon has quite some monetization plugins, but which will work with construct2? i think none of them without installing a plugin in construct2?
That's right. These are the plugins for C2: https://github.com/ludei/atomic-plugins-c2
which execution environment should be choosed for android ?
It is explained in the doc. It depends on the nature of your project. In the doc they are referred as "webview engines".
If you are developing an app, then it is better the Webview+. If you are developing a game, then canvas+ is the one which has the best performance.
The size depends on the amount of plugins you install. We removed all of them from the core, you you will notice that the component is lighter than in the old cloud <img src="{SMILIES_PATH}/icon_e_smile.gif" alt=":)" title="Smile">.
From now on, the Atomic plugins will replace the old extensions, and we are already developing the one for social integrations.
By the way, there are some users that tested the new cloud too and gave some hints and opinions here: viewtopic.php?t=117121&p=933107#p933107
Cheers