Please keep both these things I have said in mind.
All characters will require my OK to be apart of this and I will only select those players and characters I believe will contribute well to the story and work within it.
All characters will need to fit the story and fit within the group without major conflicts, due to the nature of the setting certain types of characters would be a poor choice to play. Please take this into consideration when coming up with concepts. Also consider why you would actually be willing to answer the call to hunt down objects and perform tasks for some mysterious employer, there is really no point becoming involved if your character has no motivation for the tasks. This is a story for characters not quirky concepts or "cool" classes, anime pictures or things of such nature, make the character such things with there personality and the story.
I will pick the best group of players, I will say no if I do not think you will fit within the story or I do not think your character fits in. If there are two Sorcerers I will pick the best of those players and there character which fits the story, I will only be allowing 4-6 slots so doubling up on some classes may happen but It is something id recommend. But if two of the best people for the group happen to be the same class I will accept them both over those who I think fit poorly.
Group first Characters second then me

thats the order of importance so I am least important group is most characters are in the middle with the story, together we will make a juicy sandwich of the Scarred lands.

Make the characters you want within reason and don't go too crazy or stress out to much over discussing group tactics, Ive never in all my life of playing D&D or any other RP discussed character tactics before a game or really that much during other than IC. I think that is possibly just because of my style of play and the groups Ive been with but well, I am not going to make the group suffer needlessly story will be first and well I am sure there be ample room in the group for most concepts.
Of course if you want to talk about them by all means do
Oh and Dragonrider is never really going to work well in Scarn, you may well in fact you will see a Dragon at some point in the story, but well it is likely the only one you will ever see alive. Dragons at least the ones most are familiar with don't really have much of a presence at all in Scarn. If Dragons are rare in most settings well in Scarn there like well there actually rare.