It was consistent, Miles #2 had only just been created and so had not kissed his wife or done many things, even the mundane, simply because there wouldn't have been time too. But #2 was created with all the memories from Miles #1 and since #1 had done all those things, #2 thought he had done all those things too, from waking up after creation until he realized he was a clone. #2 still had all the memories and abilities of #1 (which #2 was utilizing more in a way that made him "better" than #1), but he realized that they were not actually his own and that he was only a recently made copy of the real thing. If you mean because #2 Paul Rudd was shown in the past, I think they wanted that to show what #1 used to look like. #1 used to look (and act) like #2 but over time became more depressed and jaded. The physical change reflects that (and it was also probably largely to help the audience distinguish them more easily). Another example is how towards the end, #2 intentionally altered himself physically because he wanted his wife to think he was #1.