Hi, I'm running KDE4live with kde 4.2 beta2.
I'm trying to uninstall konqueror, but Yast tell me that Dolphin need it.
What I would like to achieve is:
1-Uninstall konqueror and using another browser
2-Uninstall Dolphin and use konqueror as file manager and browser.

Is any of the 2 viable?I'm trying to do this as I'm developing a project for a new distro that should be as lean as possible.
If the 2nd option is viable, uninstalling dolphin what functionalities and features would I loose?

I'm not sure, but seems like it is your distro specific dependency problem.
For me, the packages that will be removed upon removing konqueror are: konqueror, konqueror-plugin-searchbar and kubuntu-konqueror-shortcuts

Btw, you don't really need to uninstall konqueror to use another browser (konqueror for me is just 3.9MB of disk space). You can install the other browser and set it as default.
For example, if you install firefox, to set it as default, goto KMenu -> System Settings -> Default Applications -> Web Browser. There, select "in the following browser" option and enter firefox in the text area.

The two items you have listed as wanting to achieve actively conflict with each other. If you wish to set Konqueror as your File Manager, then open System Settings > Advanced ( Tab ) > File Associations. expand the "inode" tree and select inode/directory, then use the buttons to move Konqueror to the top and click apply.