Mumbai is the one Indian city where buyers do not need Dubai explained to them in terms of lifestyle. They need it explained in terms of price per square foot, carpet area and what the same cheque buys. A budget that takes a two bedroom in a redevelopment tower in the western suburbs buys a larger, newer, fully finished apartment in Dubai with no annual property tax and no tax on the rent, and the comparison is what drives most Mumbai enquiries we handle.
Rules that apply to every buyer in India are covered in the full India buyer guide. This page covers what is different in Mumbai.
Prime Dubai trades well below prime south and central Mumbai on a like for like basis, and the gap widens once you adjust for carpet area against super built up, because Dubai quotes actual internal area. Dubai also carries no annual property tax and no tax on rental income, so the net yield comparison moves further in Dubai's favour than the headline price does.
Yes. There is no requirement to sell anything in India, and ownership of Indian property does not affect eligibility to buy freehold in Dubai. The only real constraint is the annual Liberalised Remittance Scheme limit on funds you move out, which construction-linked payment plans are designed to work around.