Regarding the multiple occurrences of the same attributes in report - this is intentional, it happens when there is an identical relationship which has different name in each of the compared models. Because of that, one relationship is currently treated as two different relationships. As per design, attributes that are part of a relationship are bound to it (to not violate the model consistency). So when TDM sees two relationships instead of one, it also sees two attributes instead of one.
To illustrate this on an example - take Web Component entity, its relationships is named "is a" in model 2 and "is an (exclusive or) subset of digital component" in model 1.
The relationship is identical, but TDM sees two unique relationships. A single attribute migrates via the relationship to the child entity - Web Component Identifier. Since TDM sees two unique relationships, it also sees two unique migrating attributes. This is why they are treated as such in the report, even though they are actually identical.