The 144000 and no holidays are JW’s not SDA. However, SDAs are similar to JWs and Mormons in that they believe their prophet (EG White) restored ‘true’ Christianity. You must confess EG White restored the ‘true church’ in order to be baptized SDA. They do not accept baptism from other faiths. They are very controlling (look up the BITE Model by Hassan).
They also believe that anyone who worships on Sunday has the mark of the beast for starters.
According to the SDA's own website, you are incorrect.
http://www.adventistonline.com/forum/topics/the-144000-who-really-are-they
http://www.adventist.org.au/celebrating-christmas