I can understand that you want to use layers and variants in different ways as we designed them. From a technical point of view there are some layers that are aware of changing the layer variant and do a transition (e.g. the PIP Window layer will move the window around to the new position). Many layers aren’t aware of a change so they are don’t react on it. For some layer it doesn’t make sense to have transitions (e.g. because the content is atomically e.g. the Sports Game Data layer) for others it totally make sense. I have to admit that for the Lower Third layer it would make sense to actually first do the out-transition of the previous variant and then come on with the new lower third graphics of the new variant made just live. Unfortunately this behaviour can’t be generalised because each layer may have its own context what it means to switch between variants. So please make a feature request on certain layers that needs a transition between variants.
Secondly: I don’t think that the order of the variant list is a good indicator to change behaviour because this is very unintuitive.
Thirdly: Its not possible to do fade transitions between different video sources for the same video input when switching variants. This will always be a cut thought because the newly selected variant defines which video source will be active. Currently there can’t be two video source active for one video input of a layer. (Thats why there is a Video Switcher layer that can do the transitions)
I hope this gives you a bit insight on how mimoLive treats layers and variants and why it behaves differently for different layers.