Don't know If this Is correct place .

Can you see how many units you have In total from all your colonies and home planet?

Can you see total Cargo space or total firepower/armor?

The "Empire" link on the left hand menu gives you an overview of all of your planets (only fleet on the ground is displayed).

Cargo space would have to be manually calculated on your part.

For total firepower, your best bet is to use the sim with your entire fleet put in.