Background: (Undergrad applying For PhD in the US)
I need to submit 3 LOR's. I have one in mind from my personal university and 2 from other universities (with whom I have done extensive research with).
The one prof I plan to ask for an LOR from my personal university has not taught me in any class but I have done good amount of research with them (6-8 months). (This person has a professor grade with a doctorate and an extensive research portfolio and leads their own lab.)
I have another prof who has taught me several classes and I have done some research with them but have recently come in bad terms and I fear they might give me negative reviews. So I am quite skeptical of asking them now. (This person has a assistant-professor grade and no doctorate.)
Another reason why I ask this is because I am not a department topper and my courses at my university are quite mediocre, no stress upon lab components and no major project for any course. I even have mediocre attendance.
Question: Is it okay if all 3 of my Letter writers did not teach me any class during my university tenure? Will it hamper my chances in any way?