All of your nifti files should be compressed, so nii.gz instead of .nii
What you’re currently doing is using the dir entity label to denote the differences between these anatomical images. I would instead suggest using the acq entity label. So T1_MPR_cor can use acq-cor, and T1_MPR_tra can use acq-tra, and so on. I’m not entirely sure what all your anatomical varieties are, but BIDS will want your anatomical acquisitions to be 3D. Your scanner may generate acquisitions that aren’t BIDS-compliant, in which case you would simply exclude them from BIDS conversion.
Sorry, I forgot to mention earlier that for functional acquisitions, the task entity label is required in the file names; this applies to both the .nii.gz and .json files. Additionally, in the functional JSON files, there needs to be a TaskName field with the task name (e.g. TaskName: bart)
If you’re not using a BIDS converter to help transform your data into a BIDS-compliant dataset, I’d suggest checking out this list.