Not able to alter field value/s using hook_views_pre_render or views api hook functions
This is not a specific answer for your situation but I would like to advise you a better way of managing it.

Instead of rendering the views using Fields you can render each row by rendering as Content where you can choose a dedicated View mode which can be easily overridden using the standard template_preprocess_node.

This will bring a lot more flexibility in your Web application.