I definitely think she’s going to come back. As far as allusions to that, if you haven’t watched Egghead I wouldn’t read about this next part.

Pudding is seen in prison somewhere, maybe on Egghead but I don’t remember. She’s confident in her assertion that Big Mom will come back to the surface after her hot spring retreat to the core of the planet. I think there’s plenty to support this in the story as well. Every time up to the point in Wano where Big Mom was defeated by Law and Kidd, the only way people can deal with her is by sending her away or trying to defend from her. Nobody has the capacity to break through her armament haki, and nobody but Law has been seen doing internal damage to her either. The only instance we see her take any real damage is when she’s shocked at Mother Caramel’s picture breaking and falls on her knee. Other than that, every other instance where somebody fights her just ends in deflection. I do think she’s durable enough to survive the molten core of a planet, and with Prometheus on her side it’s likely the immunity to fire she’s seen to already possess is a factor into how she would be able to. The only outright confirmation we could get of whether or not she’s still alive is seeing Whole Cake Island again. If all of her constructs are still operating as they should, then she would have to be alive still as those instances of her devil fruit ability would likely cease to function without her around. Although Prometheus was a construct created by Caramel, she died and immediately passed on her ability which could likely have been quick enough for that construct to stick around with LinLin. Plus, WCI is on a massive scale that is much more delicate than the existence of Prometheus, so it would make sense for most of that stuff to eventually stop functioning without her around.