Who Owns the Standard Definition of Evolution

The problem there seem to be that you have to make assumptions in order to be able to make any predictions about a designer at all. You ask "why change something that works?" below, which seems to presume that the designer would value efficiency, but we know that sometimes designers do things in different ways for reasons like novelty or showing off, and it doesn't seem like it would require much if any modification to claim that a designer did something that isn't easily explainable for efficiency reasons for one of those reasons instead.The problem isn't that we can necessarily attribute a particular motivation to a designer and predict what a designer must do based on that, it's that we have a bunch of different things that a designer could do that evolution couldn't, and we don't seem to find any of those. It's not impossible that a designer could produce things in a way that is perfectly sensible according to evolution even though it didn't happen, and it may be possible to come up with plausible reasons after the fact for doing that, but it's getting in to pretty suspect territory. We seem to have a bunch of examples of changing something that works in life though. Many instances of marsupial and placental mammals with very similar features but that are still obviously marsupials or placentals. Ichthyosaurs and dolphins share many similar features as well, but still have the distinct features of their groups. They share many features with fish as well, but even those features have differences that are characteristic to that specific group (lungs vs gills, bony dorsal fin in fish vs boneless in the other two, tail extending in to the lower caudal fin only in ichthyosaurs).In the evolutionary view, many of those similarities are down to efficiency of function. There are just some shapes that are better than others at moving through water for example, so there's a strong selective pressure in favor of them. The key is that it's also easy to explain the differences through evolutionary history. If there's not a meaningful functional difference between which lobe of the caudal fin the spine extends in to, it's just a question of which version evolved in some ancestor and was carried on from there. Whereas the "why change what works" argument seems to now need to explain why it's different between groups but not within those groups, on top of things like why you would start building some of your streamlined aquatic creatures with gills and some with lungs in the first place.The comparison to architecture is interesting because I think it demonstrates the point people have been trying to make to you. A taxonomy of architecture styles probably would look like a hierarchy, there's probably some actual history to it since newer styles are influenced by older ones, and there are functional influences that produce similar features like steep roofs in places that get a lot of snow. But since those aren't actually constrained to features they've inherited, there's nothing beyond the local codes and good taste stopping you from taking elements from wildly disparate styles, up to the point of making a huge McMansion style mess.Or to put it shorter, when it comes to designers there's always the possibility that "why change something that works?" is answerable by "They just felt like it".

The reasoning was never "If it fits in a hierarchical tree it was produced by common ancestry". Obviously we can put a lot of things in a tree that don't even have ancestors much less a single one, and you could already do it with life since it's a subcategory of matter.The reasoning is that if the diversity of life was produced by a series of populations diverging and changing, we would expect all of life to fit in a nested hierarchy defined mostly by those points of divergence. But there are also a lot of specific features we would expect that tree to have that wouldn't be present in one you could make about galaxies or cars or whatever non-living thing.So to go back to the previous question: That depends on the nature of the similarities. We could classify both sets as life by virtue of the alien set also satisfying the definition of "life", but that doesn't necessarily mean that they will share the sort of things in common that are predicted by common descent and found in all Earth-based life.Different theories would have different predictions at that point. Panspermia would predict those similarities since it does propose that both sets of life actually do have a common origin. Multiple origins wouldn't, and would probably propose a level of classification below "Life" to encompass the products of each of those multiple origins and the characteristics that apply within that group but not to the other. The functional design theory might predict some degree of similarity but wouldn't necessarily expect it to fall in to a single tree, which would be a fresh opportunity for that explanation to predict anything with any kind of specificity.