Use the normal spectra netlist export here. (The freerouting button did call the same dialog. This duplication has been removed. The reasoning is reduced maintainance and most importantly the devs do not want that users think that freerouting is an official auto router supported by the developers of the KiCad project.)
They are still there in the v5 libs. But as they are of very bad quality they got banished into the microchip lib found in the legacy subdirectory. Maybe somebody can clean them up to get them to the standard such that they can be included in the normal libs.
Yes. Just add them using the library manager like you would any other libs (the library manager is found in the preference menus of eeschema and pcb_new.)