I cracked open three eggs in a pan and in one of them the yolk looked mottled and it looked like swirly white areas inside the yolk. (I am not referring to the chalaza stringy bit or the germinal disk). I cooked one of them and the yolk started to look a little pink as it cooked. I floated another one before cracking and it sank but slightly stood up but was also mottled when cracked. Does this sound like bacterial growth?
Your instinct to avoid eating them was spot on. As you probably already know, any type of float, even slight, and you're better off chucking them in the bin.
As for the chalaza, it certainly can be more prominent in some eggs but if you see mottled discolouration inside the yolk that's not attached to it, that can indicate:
Worming drugs and compounds piperazine, dibutyltin dilaurate and citrate;
The anticoccidial drug Nicarbazin;
Certain antioxidants such as gallic acid and tannic acid;
Feeding hens raw soybean meal;
Calcium deficiency in the hens' diet;
Thin egg shells;
Can be hereditary.
As for the pink discolouration:
"Pink or iridescent egg white (albumen) indicates spoilage due to Pseudomonas bacteria. Some of these microorganisms—which produce a greenish, fluorescent, water-soluble pigment—are harmful to humans." source: https://www.fsis.usda.gov/wps/portal/fsis/topics/food-safety-education/get-answers/food-safety-fact-sheets/egg-products-preparation/shell-eggs-from-farm-to-table/ct_index