It seems to me that all of the items described as found by LE in KA's possession in Costa Rica, were most likely related to her "unlawful flight," and don't necessarily point to premeditation of the murder. The murder of MW happened on May 11th and KA left Austin to go to New York on May 14th. Then she left New Jersey airport on May 18th, one day after the arrest warrant was issued for her. I think that during the 4 days she travelled to be with her sister, she came up with the plan and gathered the documents/info she would need to take with her as she left the country. She also was putting together information/documents she would need as she prepared to leave Austin during the 4 day period from May 11 to May 14. LE took her cell phone, so writing out information on pieces of paper make sense. She would need telephone numbers, financial information, etc., and credit cards to pay for this flight.
I think if this all was premeditated in relation to the murder of MW, she would have had more cash at the ready and more things packed and ready to go. Probably not so many aliases, either.
I can see KA working on her aliases, etc. while at the upper New York state camp while she was with her sister. I don't think, however, that any of this is related to premeditation of murder of MW. I think that the murder of MW by KA was a crime of passion, and related that night to CS's actions that including lying texts, etc.
IMO, the only argument for premeditation that can be definitively made based on the evidence that we know about so far is the fact that she had a gun with her that night. But now CS has given an explanation for how that could have come about, that she kept it in the car due to an unsettling incident of road rage in winter of 2021. It was so unsettling, that he went out and bought her a gun.