MINDEF & MHA GROUP INSURANCE for my spouse? Vs buying separately from other insurance company?

Yes, but preferably not all.

There are pros and cons to a group term policy. You can read up about that yourself.

However the 2 things I want to point out are:

1) The CI Benefit of the plan increases with age. It's not constant.

2) The Early CI benefit only covers 10 conditions unlike the 100+ over by private insurers.

I suggest to cover her death coverage using the MINDEF Term but a private plan for income protection needs due to Illness.