Can anyone with a Xth 65% XIIth 67.4 and BTech 7.73 can practically land into good B-school such as FMS Delhi, IIT Mumbai/Delhi, NMIMS, NITIE or JBIMS?

These institutes don’t give much weightage to academics.

• FMS doesn’t consider your marks at any stage of admission. At FMS, You will get a call based on your CAT score. The final admission is often based on the Group discussion and Personal Interview. For the final call, 85% weightage is given to the CAT score and 15% is assigned to the GD-PI score. 
• JBIMS also admits students based only on their entrance examination scores. 
• NITIE assigns more weightage to GD-PI.
• IITs also do the same.

Historically speaking, these institutes have offered admission to students with a similar profile as yours.