Catan Universe with 2 human and 1 computer player
Yes, you can play with both players and AIs in Catan Universe, at least on the PC version.


Choose the game to play (The Game, Seafarers, Cities &amp; Knights, etc) by click the appropriate button at the bottom of the screen.
Choose "Custom Game"
To add a player,


Click "+" next to "Add player".
Choose "Friendlist".
Enter the name of a friend.

To add an AI,


Click "+" next to "Add player".
Choose "Computer (AI)".
Select an AI name.

Repeat the last two steps as desired.


I can't answer for Catan Classic.