Actually, most things from jPCT can be found in jPCT-AE too.
What's missing:
- Portal rendering (nobody used that and it just cluttered the code)
- Shadow mapping, projective textures, shaders (because there's only limited hardware and no official software support for these features)
- Software rendering (pointless on Android)
- jPCT's hybrid rendering pipeline (too slow on Android)
- Some minor things related to lighting and colors...
Some classes have moved, some methods have changed slightly. I used the opportunity to simplify some things.
On to your questions:
jPCT-AE uses the same model loaders that jPCT uses, i.e. OBJ, MD2 or 3DS are valid options. However, parsing the files is slow on Dalvik and consumes much memory. This is why AE has an additional loader for a serialized format. This format can be written by the latest desktop jPCT only (get it from the AE-page) via the new DeSerializer class. I suggest to use desktop jPCT to load your models in any format jPCT supports, call build() on all of them (to create the normals so that AE doesn't have to do this again) and serialize it using the DeSerializer. Then load this format in AE. This is the fastest way.
For animated objects, you can use the same procedure. The DeSerializer supports keyframes too. AE supports keyframes in the same way as jPCT. However, keep in mind that the VM is pretty slow and that uploading the animation to the GPU is expensive, so keep your vertex count low.
About adding textures: You can do this in the same way as jPCT does it (you can find more information about this in the wiki) . When using the DeSerializer, the texture names will be serialized with the model. All you have to do to restore them on AE is to add textures with the same names to the TextureManager before loading the model. Order doesn't matter here, just the names have to be equal.
jPCT-AE supports blitting (as discussed in the other thread) via the FrameBuffer. This can be used for blitting overlays, backdrops, menus etc. However, blitting requires vertex uploads to the gpu, which is slow (also discussed in that other thread)...i'm trying to improve this, but i don't expect it to become lightning fast.
jPCT includes some pickPolygon-methods, AE doesn't for some technical reason. However, you can do something similar as described in this thread:
http://www.jpct.net/forum2/index.php/topic,1468.0.html. I've added that crude "calcMinDistanceAndObject3D"-method mentioned in the thread to AE, so that you don't have to use CollisionListeners if you don't want to.
Hope this helps!