I think you know this, but your best "investing" move would be to stay in the military to vest in the pension.
After that, TSP.
The same thing can be said for two individuals who each have their own trusts. But a joint trust will only say one thing in regards to a guardian. Our trust specifies the guardian.
Ok yea if you want to do that that's fine. But there are no cards that will give say 3% back on income tax payments.