I believe you have to set the comments you want to print to "show" as they will obscure other cells if printed.
what version of PC excel were you using that you could put pictures in the comment box?
Ry. It seems like you are using comments as a form of entry guidance. When data validation would be the better alternative. Comments is normally used with a review process and so when you enter a comment the default entry includes the user name of the person entering or last editing the comment. User name is pulled from Preferences>General>User Name. When forwarded to another user and they add to a previous comment their user name is placed after the prior comment in the name window so it can be identified who made what comment.
Data validation allows you to enter a cell and guidance about what should be entered along with a Cell title can be displayed. If incorrect information based on format is input an error window with graphics can be displayed.
#6 this is normally used for the user name which is driven by preferences>General>User Name
#8 This is the way comments have always been implemented unless you listed to show all comments then you could double click on the comments window.
Autohiding comments you have to right click to edit the comment.
Double clicking on the cell sets the cell for editing.
The comment box issue is not just in Office for Mac 2016 but also in Office for Mac 2011.
When creating a comment and then resizing the box the original box is kept as a reference of "here's where you started" Once you release the handle the original shadow area would be removed by redraw of the area that it previously covered. This is not occurring causing a window artifact.
Current work around is to maximize and return the window to the prior size to remove the artifact.
Check your preferences>General>User Name Field. if you don't have it filled in it will default to Microsoft Office User or some variation.
It's is showing whatever you have listed in the properties for the workbook. Depending on version this is normally found in preferences>General>User Name