Before trying to offer some general advice I need to let you know that I don't know anything about Crazytalk and I'm not the most up-to-date user of Iclone6 either. But I've built up a good basic knowledge of the world of 3d as used by hobbyists such as myself and beginners for whom everything is new.
You've begun using Iclone at a time when Reallusion has provided us with a new means of creating all sorts of characters using the Character Creator package. Many users have been eagerly waiting for an update which will permit them to create their own clothing for these characters. But that is for the near future and for those who are capable of modelling using 3rd party software.
Prior to Iclone6, previous versions of Iclone had their own character bases. Several generations of them. The way to clothe these characters in all sorts of styles was to purchase Clone Cloth from Reallusion.
Iclone's earlier characters weren't created as one-piece meshes - they consisted of head, upper body, lower body and so on. Clone Cloth replaced, for example, a female upper body with an upper body mesh clothed with an outer layer clothing mesh.
If this outer layer had long sleeves, then it could be textured in such a way that the sleeves, for example, could become invisible, exposing the arms. So the upper body Clone Cloth could be made into a short-sleeved shirt, a vest, a garment with holes in it and so on. It could also be coloured in any way. Iclone was designed to launch Clone Cloth templates in a paint package of the user's choosing so that the user could paint out the sections not needed and so on.
What I'm coming to is that, if you are prepared to use older generation characters for a while and are prepared to buy Clone Cloth for them, there is a huge marketplace full of clothing available from Reallusion's vendors.
Individual Clone Cloth bases can be bought gradually. but note that there are at least two 'generations' of Clone Cloth to match different generations of characters issued over the years. I don't know whether Clone Cloth meshes can be Physics enabled for realistic cloth motion - someone else may be able to say.
The above was just a thought for you to consider. It may be that you want to be fully up to date and would prefer to wait for vendors to create new suitable clothes for Iclone6.
On the question of creating props, it is possible to assemble objects of your own and animate them just by using the basic 'building block' props that come with Iclone. Few people choose to do that, however, because it is a primitive and limited way to model; nevertheless some individuals have done so very well as a labour of love.
If you have 3dXchange Pro you can look at the world of DAZ for all kinds of medieval items. There are many beautiful medieval buildings made for Poser also - but I prefer to refrain from linking to another store when I am here on Reallusion's forum.
If you want to get into creating your own things then you need to look at modelling programs. I use Hexagon, from DAZ but many people find it to be full of fatal bugs on their systems. I also use Carrara which is a well featured, all round 3d package but is viewed as being dated with no future (not by me!). In fact I play with animating in Carrara as often as I do with Iclone. Wings 3D and Silo are other modelling programs.
Apart from modelling packages, there are sculpting packages such as Zbrush, 3dCoat or the free Sculptris.
Blender is free and can do everything you could wish for but at this stage it would be like trying to swallow a whale.
Remember that slideshows of still images could work well in a classroom. You could use these in worksheets, revision notes, etc. and you could get into animating these basic scenes later.
Hope that some of this is of use.