Man, Ba'al and the Joker, what a match made in heaven.
Also, the Yautja would fucking
love the Joker. I can actually see them deliberately not killing him just because letting him go so they can hunt him again is
way more fun than ending the hunt.
Unfortunately for the multiverse, the SG1 setting does in fact have devices for jumping between dimensions. One played a major role in the lead up to the season one finale. So, since Ba'al's race stole much of the tech that went into that device, then it stands to reason that, given time and access to the right equipment, he could cobble together a way of getting home; this is made more likely when you consider the DC universe also has multidimensional tech, and while Joker isn't likely to know how to build such a device, he would know about such things and may advise Ba'al to make one.
Plus, we have no idea whether or not such tech exists in the Aliens/Predator universe. No, we haven't seen any such tech, but that doesn't mean it's not out there. After all, why would a Hunting Party bring a gateway to another universe down with them on a hunting expedition?
Point in fact, one could say there is proof they do have such tech; a limited series crossover between Batman and The Predator back in the 1990's. Yes, it is basically non-cannon.... Unless it isn't.........
He's not in the Stargate universe, he's in the Aliens vs Predator universe, as is Ba'al. No dimensional travelling technology to be found there, just fucktons of Yautja,
more fucktons of Xenomorphs and a handful of grizzled Space Marines who keep getting in
way over their heads.
And while Ba'al is from the Stargate universe, the only dimensional traveling tech in Stargate is Ancient tech, the Goa'uld never demonstrated any ability to travel between dimensions, and even if they did the Ancient tech requires that the dimension to be traveled to also invent exactly the same technology. And while Goa'uld tech was derived from stolen\salvaged Ancient tech, the Goa'uld themselves never really understood most of what they found. IIRC canonically like 99% of the Goa'uld tech-base was the product of one genius Goa'uld who reverse-engineered a bunch of Ancient stuff and then got dead, with Goa'uld technology then basically stagnating for thousands of years until Anubis showed up with his stolen Ancient knowledge.
So the odds of either of them ever coming back are pretty minuscule, they
are however quite likely to terrorize the AvP universe for awhile, but that universe is a hellhole so no-one will care.
e:
Yautja1: What are you doing with that prey?
Yautja2: Catch and release, I am fixing it so that I can let it go and hunt it again.
Yautja1: But why would you do such a thing?
Yautja2: Come with me on my next hunt and I will show you.
[Some Time Later]
Yautja1: What the?! Where the hell did it get
high explosives from? And how did it hijack that shuttle anyway!?
Yautja2: I know right! Every time I think I've figured it out, it does something
ridiculous!
Yautja1:
THIS IS AWESOME!!