Colleges in Delhi

You will have to wait till the cutoffs are out. You can also refer previous year's cutoffs.

Yes, there is BA in English degree in IGNOU.

The forms will be out in the month of May.

No, you have to fill only the application form provided by DU on its website for UG admissions.

All three branches are relatively similar. All deals with the mechanical part of engineering.
Though in automobile engineering, you mainly deal with engine and motors of vehicles.
Whereas in mechanical engineering, you deal with every aspect of mechanics that is there.
Mechatronics is a combination of mech and electronics where you deal with combined electronic and mechanical aspects of things. This is a relatively newer branch and should be pursued from good institutes only.

You have the option of pursuing hospitality, tourism, marketing, sales, etc. It depends on your skills.