Seems to be correct for the II and S/II. There are also C551 which are Citation 2 SP (single pilot)...these have been seperated from the rest with their Citation C501 counterpart, although they are basically the same aircraft, just with lower MTOW (C551) and some requirements as A/P, boom mike , Headset etc int he manual...
The XL has already 2 follow ons, the XLS and the XLS+...
The list should look as follows:
This is a classrating (C501/C551):
Cessna 501 Citation ISP
Cessna 551 Citation IISP
This is one typerating (C500/550/560 - differential trainings required between certain types):
Cessna 500 Citation I
Cessna 550 Citation II
Cessna S550 Citation S/II
Cessna 560 Citation V
Cessna 560 Citation V Ultra
Cessna 550 Citation Bravo
Cessna 560 Citation V Encore
Cessna 560 Citation V Encore+
This is a different type rating (Differential training between XL/XLS and XLS+ required)
Cessna 560 XL Citation Excel
Cessna 560 XLS Citation XLS
Cessna 560 XLS+ Citation XLS+
Have a look here as well:
http://www.easa.europa.eu/certificat...t-12032013.pdf
for q2, the rating you get is the 500/550/560, now you may fly what you have trained on. Lets say thats a Bravo sim, you`d need a differential training to fly a C500, a 550 or S550 or a 560. (Pages 11 and 4 of the linked list)