For this, I would suggest enabling Cups Network Printing (browsed), if you haven’t already. Then your network printer should be picked up automagically in either GNOME or KDE.
As far as analogs for your extensions go, I know that you should be able to “recreate”:
- AppIndicator (standard in default config)
- Blur my Shell - This is theme dependent. Blurred, Solid, and Transparent themes are all available. The default theme is a mostly solid theme, BTW.
- Clipboard Indicator (standard in default config)
- Dash to Dock - The default is more like Dash to Panel, but this can be changed.
- Desktop Icons NG (standard in the default config)
- Frippery Move Clock - the items on the panel/dock can be rearranged