In regards to your first question, it looks like you are using dual axis MIN(Number of Records) or MIN(1) for your graphic crosstab, no? To get rid of the lablels at the bottom of the column, double click the column, which should bring up the "Edit Axis" menu. Erase the axis label on the first tab, and on the second tab, remove all tick marks.
For the second question, you're right, you can't add a tool tip description for dimension members in a crosstab. Is there any reason you don't want to add the description and use the tool tip for the regular marks within the same row? There doesn't seem to be much of a difference in my mind between hovering over the 2nd column and the 3rd to get a project description.
Thanks, I will try this for the first option.
The reason is that the individual marks within every column and row have different descriptions of their own.
The project description belongs on the name of the project, then the traffic light has a different tool tip, and so on..