Don’t think so. And unfortunately the Animation Manager doesn’t allow multiple selection - Andy?.
I’m familiar the irritation of fiddling with hidden layers and objects. A hint is to install a keyframe at tick 0 making every layer and every object visible. The actual animation then starts at tick 1 hiding or disabling whatever is necessary. This way you can always turn to the keyframe at tick 0 in order to get a hold on every object.
You can first of all insert 1 tick at tick 0 (use BongoTimelineInsertTicks command). All keyframes (every type) are shifted right without making selections. Then you can install the basecamp keyframe for every object and/or layer. You can take your time to make sure you have them all. Maybe use the Animation Manager as a guide.
Finally the BongoScaleKeyframes trick can take place. Whew!