The general rule of thumb for retirement is to take your expected retirement expenses/month time 25 and have that in your retirement portfolio (cash/stock/bonds/etc). You can then pull out 4% and the money should last you at least 30 years, generally forever. You can check FIRECalc for simulations.

My only thoughts on your situation is you are assuming high return rates, and not a realistic retirement amount. You need to remember, you must pay out of pocket for health care, so budget 1k per person for that.