So what can a mammal evolve to?
A mammal can evolve to a different mammal. That might be a small change, or over time a larger change. The original population of
deuterostomes have evolved over time into many different forms of deuterostome, including humans. We are deuterostomes.
With science we can observe and test thus it can prove many things like the biological parents of a child.
Science does evidence. If there is a 98.7% DNA match then that is called "proof", but that is actually a way of saying "overwhelming evidence", and shorter to say as well. What a court will accept is different from what science will accept. Scientific measurements come with a level of uncertainty, hence they are evidence, not proof. For example, the value of the fine structure constant is 0.0072973525693(11). That (11) at the end is a measure of the error in the value, in this case between ...5704 and ...5682
If a land animal is evolving into a sea animal it would need to add information to breathe and swim under water.
No. It would just need to evolve to hold its breath for longer, as whales and dolphins have done. Evolution can follow many paths, not all of them obvious. As to information, evolution can easily add information with insertion mutations and duplication mutations. These mutations have been observed to happen repeatedly.
The fossil record doesn’t support the evolutionary claim and thus the idea of punctuated equilibrium came along but there isn’t any actual evidence for it.
Your sources are lying to you again. The fossil record supports punctuated equilibrium.
So finding an animal that is in the middle of evolving into another animal would falsify evolution?
An animal in the process of evolving obviously does not falsify evolution, it supports evolution. A chimera, composed of parts from two or more different species, such as a mermaid or a pegasus, would falsify evolution.
You appear to have a misunderstanding of what evolution does. For example, about one third of humans have some type of lactase persistence mutation. Other humans have mutations that adapt them for high altitude; those mutations are found primarily in Tibet, the Andes and in Kenya. Mutations in the real world are not like they are in comics.
Humans create and design things that are similar and completely different all the time so we have scientific evidence that an intelligent designer can do both.
I did not ask for similarity or difference. I asked for something that your proposed designer could
not design. Absent such a description, then ID is lacking a falsification criterion, and becomes irrelevant as science.
Your fairytale origin story isn’t necessary for actual science.
Fairytale? My origin story does not have a talking serpent and two magic trees. I know which one looks more like a fairytale. Do you?