QGIS, LISTMap Sources and Printing Maps

It's been more than 4 years since I last posted about generating maps to print, and I'm wondering if anyone has made any progress as I obviously haven't been trying. I just did a fresh install of QGIS recently and following the list_spatial_web_services_user_guide.pdf and a helpful video on youtube I have nice clean LIST Topo basemaps loaded into QGIS with the custom scales added. I still have a bunch of questions though and I'm going round in circles trying to find clues.
1. Custom scales as defined in the list spatial web services guide work great (everything is as crisp as expected) when running WGS84 / EPSG3857, but if I overlay the 1:25k Topographic Index (outlines of all the 1:25k maps and names) then the rectangles for each map outline are skewed. If I run GDA94 Zone 55 / EPSG28355 as suggested elsewhere, the rectangles are nice and horizontal but the maps don't display well at the custom scales. Is this a problem with different LIST layers being setup differently, is one outdated, are there other custom scales I don't know about, or am I missing something ?
2. Maps like the new 1:50k downloadable from TASMAP or NSWTOPO maps on Avenza look like they use much better vector data for contours etc. Are there public sources of such data ?
3. I looked for data to add, like TASVEG layers in LISTMap (as mentioned on the NSWTopo Maps) but looking in the LIST browser version they're not much use as they're just blocks of colour overlay. What do I need to look for to either edit that information or style it to use in QGIS ?
4. Even once I find good sources of vector data for watercourses, contours etc, how can you manipulate these with custom colours or styles ?
I'm trying to learn but I'm a bit over my head with all the terminology. Any suggestions appreciated.
1. Custom scales as defined in the list spatial web services guide work great (everything is as crisp as expected) when running WGS84 / EPSG3857, but if I overlay the 1:25k Topographic Index (outlines of all the 1:25k maps and names) then the rectangles for each map outline are skewed. If I run GDA94 Zone 55 / EPSG28355 as suggested elsewhere, the rectangles are nice and horizontal but the maps don't display well at the custom scales. Is this a problem with different LIST layers being setup differently, is one outdated, are there other custom scales I don't know about, or am I missing something ?
2. Maps like the new 1:50k downloadable from TASMAP or NSWTOPO maps on Avenza look like they use much better vector data for contours etc. Are there public sources of such data ?
3. I looked for data to add, like TASVEG layers in LISTMap (as mentioned on the NSWTopo Maps) but looking in the LIST browser version they're not much use as they're just blocks of colour overlay. What do I need to look for to either edit that information or style it to use in QGIS ?
4. Even once I find good sources of vector data for watercourses, contours etc, how can you manipulate these with custom colours or styles ?
I'm trying to learn but I'm a bit over my head with all the terminology. Any suggestions appreciated.