1) Depends on the type of research and on the type of residency program you're interested in. Having research experience certainly doesn't hurt, but research isn't usually the main focus of hospital residency programs. Any experience that shows initiative, leadership, collaboration, communication skills, etc is good to have. Clinical research experience where you end up presenting a poster or being an author on a publication is a good way to stand out, and working closely with a faculty member as part of your research experience will also help you get a good LOR.
2) GPA, clinical APPE rotations that align with the program's focus (e.g., if you are primarily interested in critical care focused residency programs, it's a good idea to have some critical care APPE rotations), LORs from people the residency program is familiar with (and respects), leadership positions in student organizations/pharmacy school, employment during pharmacy school, and making a good impression when talking to the current residents at Midyear residency showcase the year you apply.