[Locked] AEM - Adding custom css file to Adaptive form template. No theme usage

Hi All, 

Here is my requirement.

Req: Add a custom css file to Adaptive Form Template. Hence, it will load at forms-template level. Business requirement (technical) says no "theme" usage. I have given two approaches, one is by using custom theme implementation and another one is manual loading in  from form container.

Please let me know any other approaches. 

--Thnx/Santhosh