Game ending scenario - runner goes into DBT

[Dakota]

I brought this up once in the other thread, but didn't ask again there since it was a bit off the topic of the appeals and such.

Bases loaded, bottom 7, R1 is the winning run. 1 out. BR gets a walk. R1 crosses home. All other runners enter the celebration and do not advance to their bases.

In FP, this is a live ball situation. An appeal cannot be made until the runners are no longer eligible to complete their base-running duties. That can't happen until the runners enter DBT. However, if the runners abandon their attempt to advance and enter DBT, that is not an appeal. They are merely out.

Does the umpire declare them out rather than wait on the appeal? If not, why not?

If, in the celebration, one or more of the active runners pass each other, are they also declared out? If not, why not?