Confused with Unit Limit CCC to UC

[mikemac]

Or do units from undergraduate courses taken at other UCs add to the 70 units received from a CC and have the potential to bring you above the unit limit?

This. See http://admission.universityofcalifornia.edu/counselors/files/quick-reference-2017.pdf page 30

You may not have replaced the D you got in Chem since says

UC courses must be repeated at UC, but not necessarily at the original campus.
http://admission.universityofcalifornia.edu/counselors/files/quick-reference-2017.pdf page 25

Another issue may be from your time at UCR since they require

Be in good academic standing (2.0 GPA or better) at the last institution of attendance and at any previous UC campus where the student was enrolled in a regular term (e.g., fall, winter, spring).
http://admission.universityofcalifornia.edu/counselors/files/quick-reference-2017.pdf page 25

If they are not in good academic standing, they are advised to contact a college/school advisor at the UC campus they attended or are attending to learn how to improve their academic standing.
University of California Counselors

People here are happy to try and help, but IMHO your situation is too complicated to get your counseling from the internet. You should find a good xfer counselor at your CC and also talk with the UC reps that visit your campus.

Best of luck to you, it sounds like you have turned things around, just work your way thru the bureaucracy to get your enrollment issues resolved