Colleges in Mumbai

Hello Sejal,
Admission is through counselling based on the rank obtained in Maharashtra State Common Entrance Test (MHTCET). Vacant seats will be filled by the institute based on the rank obtained in JEE-Mains.
For more information please visit the link below:
https://www.shiksha.com/college/thakur-college-of-engineering-and-technology-kandivali-east-Mumbai-47539/admission

You have a good score in mentioned exams but the admission will be made through CAP-based score obtained in National Aptitude Test in Architecture (NATA).
For more information, please visit the link given below:
https://www.shiksha.com/college/rizvi-college-of-architecture-bandra-west-mumbai-22909/admission

You have very good marks but for admission, you have to appear in counselling procedures.
Admission is through counselling conducted by Directorate of Technical Education, Maharashtra based on marks obtained in 10+2/ Diploma and score obtained in National Aptitude Test in Architecture(NATA).
Selection parameter and weightages:
10+2/ Diploma marks - 50%
NATA score - 50%

For admission in Manav Rachna University in engineering, you have JEE marks.
And in architecture, you have NATA, so don't worry. You have lots of choices for admission in various colleges.
For more information, please visit the link below:
https://www.shiksha.com/b-tech/articles/list-of-popular-colleges-accepting-nata-scores-blogId-10681

Yes, you can get admission.

You need to give the NATA exam (preferably before the end of May) and then in the month of June-July apply for the admission process of DTE. If your NATA score and 12th percentage are really good then you might get into Sir J.J. college of Architecturing.
Admission to B.Arch. is done on the basis of valid score obtained in NATA/ JEE Main 2018.

Yes, they will accept JEE paper 2 and NATA scores.

For mechanical branch it was around 500-1000 state merit rank. For comps it was around 1600-1800 and for IT elex ExTC it was around 3000-3500 till CAP2 with percentile of around 96. If you have patience then i will suggest to wait till CAP3 ie. Counselling round as cutoff there was around 6000 for comps and 11000 state merit rank for IT. So if you have less score then keep calm and wait till CAP3. You will easily get into the college you want.