Simple plugins and behaviors which are logic-only (only make calls to C2's engine) should be fine. However, any plugins which use browser features, such as any DOM calls, use of Image() or Canvas() objects, or controls like listboxes or input fields, may not work or may need changing. Also note anything using jQuery will not work because jQuery is not included in these exporters. The official Button and Textbox plugins are disabled for these exporters because there is not currently an easy way to get them working.
Please test your plugins and behaviors work when exporting to CocoonJS and (when it comes) directCanvas. This is important to prevent users who use your addons finding their projects are broken in CocoonJS or directCanvas, and if the problem is caused by third party code we can't officially help them.
Thanks! If you have any questions please ask them in this forum and we'll do our best to help. We may also need to collaborate between ourselves and appMobi and Ludei to get features added that popular third party addons use so we can improve overall support for Construct 2.