You can arrange a Jain vivah in Mumbai through nearby Jain Sanghs, Derasars, and Jain community trusts, especially those that conduct religious and community events. Some useful places in Mumbai / nearby Mumbai region are:

• Shri Swetambar Tapagach Jain Sangh (Gruh Jinalay), Mumbai — Prem Sagar, 4th Floor, Majgaon, Sardar Balvant Singh Marg, Mumbai-400010. ( jainknowledge.com)
• Shri Sumer Tower Jain Charitable Trust, Byculla — Sumer Tower, Motisha Lane, Byculla East, Mumbai-400010. ( jainknowledge.com)
• Shri Byculla Agripada Jain Sangh, Byculla — 669, B Mahavir Estate, Byculla Station Road, Na. M. Joshi Marg, Mumbai-400027. ( jainknowledge.com)
• Shri Ghatkopar Jain Shwetamber Murtipujak Sangh, Ghatkopar East — Mehta Marg, Ghatkopar East, Mumbai-400077. ( jainknowledge.com)
• Shri Vagad Visha Oswal Shwetambar Murtipujak Jain Sangh, Goregaon West — CCI Colony, Mahatma Gandhi Road, Goregaon West, Mumbai-400062. ( jainknowledge.com)
• Shri Marudhar Visha Porwal Jain Sangh, Colaba — 30, Rajawadkar Street, Colaba, Mumbai-400005. ( jainknowledge.com)

For a Jain vivah, these places are usually good starting points because they are connected with Jain community members and religious activity. ( jainknowledge.com)

You can also check a nearby Jain temple/derasar in your area and ask for the Sangh office or community hall booking. For example, Jain centers are listed in Vikhroli East, Vashi, Malad West, and Mumbai Central/Byculla areas. ( jainknowledge.com)

If you want, I can also give you a short list of Jain marriage halls in Mumbai by area.