Hi Alekzsander! Welcome!
flatulentFuzz: Hi Samuel!.. Glad you will be joining!.. A dog would do great!
Hi Giorgio! Thats great! Please feel free to post any reference to this thread that Rebecca has provided: http://forums.cgsociety.org/showthread.php?t=643678
I think your idea of “zsphere, scuplt and then pose” will do fine. It is not at all difficut to pose after sculpting, although you may have to apply a few corrective tweaks.
Hey Nitin! Started already! bless you! Good mesh!
TheRazorsEdge: Hey Felix! Great! you may upload the mesh and post the link on the reference thread if you like. 
psebesta: Hey Paul! That’s probably the cutest gecko I have ever seen!! 
vlad74: Hi Vlad! Welcome! There is always a first time!! 
Buexe: Hi! The cheetah looks great!
… only, that second pose doesn’t go with the theme (“in repose”/at rest) 
Ravis3057: Hey Ryan!! Great choice!!
sapienz: Hi Max! Triangles usually cause “pinched” areas where it is difficult to sculpt, so it is best to hide them in places where they won’t be seen. As for 5 sided faces, Zbrush tesselates them into (i think) a quad and tri each while importing, so you face pretty much the same problem there!
Hey Glenn!! Awesome!! I am loving it!:bounce:
pencil-head: Hey Tristan! Its looking great!
Dragons0088: Hi Luke!.
1: Since the theme is “animal in repose”, I would rather that you modeled the entire body along with the head, unless you could imply that the dragon is at rest by its expression or something.
2: It shouldn’t be too dufficult to join them after, though I would recomment that you make the whole base mesh even though you plan to sculpt only the head at first; you could just hide the body area for faster working.
3:it is your choice, but if you propose to have the mouth closed for the final sculpt, I guess there isn’t much for modeling it open.
4: Again your choice, but imo, teeth are better kept separate from the main mesh.
5: Since the spikes are apparently so many and so close together, it could get really confusing if you model them all into the basemesh. I would suggest adding the spikes later-on as subtools or using insert mesh or something.
6.no, I dont think this will be too difficult for you to attempt(I believe nothing is, if you are patient enough!) Approach it one step at a time, as you would approach a drawing: Gesture first, then volumes and then detail. Happy sculpting!
AUMAKUA: Hey Nick! Awesome!!:bounce:
kdubayoo: Hi Kelly! Welcome!! you came to the right place!! No pressure, no stress! Just sculpt, learn and have fun!! Yes, it would be easier to start of with a nuetral, symmetric pose. Please have a look here if you need a once-over on zbrush basics, including Transpose. Also, please feel free to post any specific doubts/problems… There are so many experts already participating, and yet to join! … and I will be only too pleased to be of any help, in my own way.