I just finished this a while ago, an update my sona's general anatomy, such as her wing structure, she can still stand up like in the last pic, but this is how she generally looks.
Background is from here -> http://austiniousi.deviantart.com/art/Ponyville-Background-324408425
and yes, she is a Deadly Nadder
Deadly Nadders © Dreamworks/Cressida Cowell
Capricorn © Me
MLP:FiM © Hasbro