Hi imett,
I was waiting to see if someone more experiencied than me could help but I will try anyway. When you are talking about in which ground you should connect the component I really don't understand what you mean, there's only one ground, the ground plane in the bottom; the component should connect to a copper spot filled with bias to make a good (ideally free of parasitic) ground.
My suspect about this hole you see at evaluation boards is that it's a non-standard fiducial mark for automatic pick&place machines(usually local fiducial for fine pitch component is a solid circle of copper with solder mask cleared and a good clearance, but I see machines that are able to handle with any geometry).
You said that many board filled the ground along the signal trace with bias,are the using this configuration?:
GND
SIGNAL
GND
if so it's a coplanar line, and yes you should fill with vias(every lamba/20 or so). If you use microstrip ground must be placed at a safer distance from the signal trace because calculations of impedance assume that only the ground plane in the bottom layer is present.

Other questions arise if you have in the same board RF,power and digital circuits. Then power and ground usually are splitted and connected in
a star point.
Hope it helps,
PD:there's a tutorial about RF design available atwww.jlab.org/accel/eecad/pdf/050rfdesign.pdf