Your combined net worth would be about $800k assuming your flat is now worth $400k. By the time you retire in 25 years time, your sources of passive income are:

1. Rental from condo (paid up at 65) maybe $3k pm.
2. CPF Life maybe $1.5k each or $3k pm combined.
3. Allowance from children $1k pm combined.
4. Room rental from HDB flat, $1k per room or $2k for 2 rooms.
5. Stocks dividends $12k pa or $1k pm.

Total passive income $10k pm.
Expenses (just two retired persons) $4k pm (assume no maid and no car).
Savings $6k pm (reinvested in dividend stocks to give higher dividend income).

Summary: You are a high achiever and will retire well.