I had the same questions not too long ago. Being fairly new to D/S and not having Poser, but wanting help with animations, I was weary about purchasing animation packages for fear they would not work in D/S.

I have yet to buy any of these products, but I have found several for free to experiment with, www.es3d.com and www.renderotica.com. They all seem to be nothing but a series of Poser -pose files so just like normal pose files for Poser, they work in D/S in my experience.

The only thing I have noticed is that they have been difficult for me to modify. If an arm is say, to close to a breast, you have this problem for how ever many frames this problem occurs. Because it is a preset pose, I have not been able to make adjustments like I normally would by tweening, meaning I had to pose each frame individually. This can be tedious when you have this across fifty frames or more. This is not to say there is not an easier way to do this; I just have not found it yet.

The good thing is,  you can  save  the frames you want individually and use them outside of the complete animation.

As for your gif question, I have not seen any way to output a gif from D/S, but I have taken my images from D/S and imported them into GIMP, www.gimp.org, which is free and one heck of a program. I use it almost as much as D/S nowadays. If you have not tried it yet, I would highly recommend it. It has a bit of a learning curve, but it's well worth learning.

I hope this has been helpful.