I'm kinda curious how titty goddess is supposed to be an insult, lol.
It does fit with the idea that no matter how much of a cool devil Homura makes herself out to be, she's still an inept dork on the inside and can't come up with good insults.
The author didn't make it totally clear, that was one of the possible timelines in this world, and also likely a timeline which has already happened (remember we know of at least 104 confirmed ones, maybe more).
I don't think Homura ever died in her loops.
It's not one of her loops, it's an alternate timeline. Basically, it's one of an infinite number of timelines/realities, a la the whole "Multiverse" concept.
I finally just noticed the tears in Madoka's eyes in the final panel... That means she was crying with happiness as she dominated Homura! Oh god, the HHHHHHHG!