Is entittyfieldquery result can be loaded into select list?
Can this array can be loaded into select list directly? or we need to apply node_load_multiple on $results array.

A FAPI select list expects an Array with id and title. An entityfieldquery returns only a list of IDs unless you get creative. Typically you perform extra work to load fields you want to show as text in your select field. You can do this via SQL, node_load a view resultset ... whatever means you're comfortable with.

EDIT

Well I didnt say you have to use node load. There are various extensions to EFQ that let you use community created EFQ classes:


The most recent is https://www.drupal.org/sandbox/mikeytown2/2209909
A slightly older less pretty module is https://www.drupal.org/project/efq_extra_field