Sirius is a blue star meaning Superman's power increases to much more than he was under a yellow star. While under a blue star he gains another ability called 'Superman Vision'. Using this power makes the person he used it on have the same power as Superman. So he could use it on Goku making him useful in this fight.
This Shazam and Black Adam, well Teth at least knows some magic so Superman WILL be at a disadvantage if he takes on Teth. I dont know whether Goku will also have the magic vulnerability that Kryptonain's have. Since it was only 1 story under a blue star, lets just say Goku would gain the powers that Superman has, without the magic vulnerability.
Superman's hope of winning would then lie in Goku. And with his ITM, Goku could help out a lot. If he doesn't do anything stupid like amplify their power or use the 'Superman vision' on his foes thinking it would be a fair fight.
My vote at this point in time goes for Superman and Goku.