Can Corona with Blender be used to render out animations using online Render farms like rebusfarm?
Sorry can't help much, however if a render farm provided the plugin and corona then I can't see why it wouldn't be supported. No idea if any of the farms support it though.
I can't view textures in the viewport even when scaling the textures. Does this work with materials in the node editor/ material tab?
This only works in specific scenarios, and only with nodes. Possibly something that should be looked at :)
Can renders be stopped and resumed?
No, hoping for some work on the standalone to allow renders to be restarted, this might also enable pause/resume?