Can we write php conditions in view field templates?
No. Do not make a view that pulls a nid, then do node_load in the template. This will be a performance killer.

You should create a view mode using Entity View Mode module, add the fields to the display, and theme it with node--node-type--view-mode.tpl.php. Then the configured View only has to show 'Rendered Content' - and pick the view mode. Then you're done. 

See: https://www.youtube.com/watch?v=wcskTtvR6Mo