Why doesn't the "Request translation" button show at node/%/translate for some of my content?
This is likely an issue with the configuration of the main content block. Visit Structure > Blocks > and click on configure for "Main page content". Make sure the visibility settings are correct for your site, especially Pages and Content types.
Why I see EntityMetadataWrapperException about missing data property plugin at admin/config/regional/tmgmt/translators page?
This caused by the conflict with UUID module. You should use UUID version > 7.x-1.0-alpha3