If I understand correctly, your problem is that existing walls are showing up as halftoned and without patterns in views having their Phase parameter set to the New Construction phase, and you want them to be darker and/or display their patterns. Is this correct? If so...
1. Take a look at Manage > Settings > Additional Settings > Halftone / Underlay - Here you can adjust the darkness of the halftone setting.
2. Take a look at Manage > Phasing > Phases. Look at the Graphics Overides tab. The chart is not referencing phases as an absolute. It is instead referencing elements created on the timeline relative to the current view's Phase parameter setting. In other words, the first row dealing with Existing elements deals with all elements created in a phase prior to the one a view's Phase parameter is set to. On this first row, you can change the settings for patterns (among other things), and even select whether they're halftoned or not in the first place (in case you aren't happy with the adjustment setting I mentioned in #1 above).