Now that you have the player model flexes, you can use them as a reference in order to flex your item.
Open your item in blender. Go to the Object Data tab
. Go to ShapeKeys.
This is where all the flexes will be stored. Add a shapekey using the plus button
It'll create a Basis Key. That's your base model, non-flexed.
Now, add another one. This will be your first flex. Now you want to rename it to match it's actual ingame name.
Open the player .QC that you decompiled in the first step. Go to the line $model "class" etc. The flexes names will be right under it.
In this exemple, the first flex is CloseLidLo. So you'll rename your shape key to match that.
Now you can check if your item needs to be edited to match the new flex. If it does, just go to edit mode while having your shapekey selected. Be sure to not edit the basis key, as it'll apply the change to every keys.
Make the modifications and go back to object mode.
Once it's done, you can use the sliders to see your flexes in movement (the number next to your shapekey being the influence of the key on your model)
Redo this for every flexes.The first 2 flexes should be the eyelid ones, which won't probably need any change to your model. The OO, OH, EE... ones are based on the sound they're supposed to make. The scaredupper, evilsmile, etc are self explanatory.