What was Bothan involvement with the Rebellion according to Disney canon?

Question

In "Return of the Jedi", Mon Mothma briefed the Rebellion leaders on the plan to assault the Death Star II, and famously said the following line:

Many Bothans died to bring us this information.

In Legends continuity, it was established that the Bothan deaths occurred when Vader single-handedly slaughtered an entire intelligence cell of Bothan operatives while attempting to retrieve the plans. However, when the canon changed, both that event as well as the prior events which lead to the Bothans having the information was ret-conned out of existence.

Therefore, in the Disney canon, what was the Bothan involvement in the Rebellion's plans, and how did their deaths come about?

Answer 1

In current Canon, separate teams of Bothans apparently retrieved the Death Star II plans and the Emperor's schedule, with at least the latter dying in the process. In From a Certain Point of View: Return of the Jedi, Mon Mothma goes on a personal mission to retrieve a dead drop sent by a team of spies containing information about the Emperor's whereabouts.

"Not this time. The team entrusted with this particular droid was so close to accessing information about the Emperor, Ràq. The only reason it would signal at all is if—" they're all dead. She doesn't say that. "Is if they accomplished their mission and sent it, and the data they'd gathered, to me, directly."

[...]

Mon pulls the protruding cloth-wrapped datacard from the small hatch. The tiny piece of fabric tucked around the card is handwoven, burned, and bloodstained.

She sighs. Many have died to bring us this information. And she will make their sacrifice worthwhile.

[...]

This new item is something she hasn't had time to brief the admiral on, arriving as she has so late, on the dusty trader's shuttle. With the pilot destroyed, no one would know the risk she's taken. But there had been no other way. And now Ackbar is eyeing her curiously.

[...]

She speaks clearly, with precision, acknowledging the sacrifices many have made to bring the rebels the Death Star plans. She pauses, knowing that the admiral will prepare them for what lies on the moon of Endor below. And then she adds, "Most important of all, we've learned that the Emperor himself is personally overseeing the final stages of the construction of the Death Star."

_{From a Certain Point Of View: Return of the Jedi, "No Contingency"}

For some reason, the Bothans themselves are never mentioned by name in the story, but the actual lines from the film mention only Bothan spies as the source of both pieces of intel, so there's no one else she could be talking about. It's worth noting that post-Disney canon has not yet defined what Bothans are, so this reluctance on the part of the short story's author could be related. As far as I know, the mission to retrieve the plans themselves remains unexplored.