I have the same problem

1. if you want create enabled, you should use built in filters for search, and action should open view vith filters enabled by default
-give filter a name in xml, and pass it trough context in return, like: context : {search_default_filter_name : 1} 
- use domains in your return...
 

2. if you want to use sql querry to fetch the data,
it should return list of record ids and in your return add a key: res_ids:[listo of ids]   (this aproach does not need domain!)
OR :
domain : [('id','in', [list of ids])]  

Create button is enabled by default on all editable views ( need to set create="False" to remove it!)
But in order to use it, you need to have some values in context (defining default values etc..)

as for other return values, look in action definitions inside xml files, and use all attributes found there... 

hope it helps..