I've done a bit of a research about FH plastics, I've seen hundreds of photos and I believe I can help you

Question 1: These little plastics (and the single green balloon) go... wherever you want! Most likely they included these little plastics for the user to add wherever they like or to "mask" broken plastics, or even as plastic protectors.

Question 2: First image has plastics correctly installed. Second image is correct only if your FH is a prototype, otherwise in later releases this blue balloon together with the clear post go behind the mirror (strange fact... I know). Moreover you are missing the hand plastic that points to the hole. Third image has the little red plastic all wrong. The two "legs" of the small red plastic on the back must touch ("hug") the back screw and the blue balloon must be in the middle between the two screws holding the red plastic. Fourth image has the small triangular plastic upside down. Fifth image has the green+blue balloon plastic upside down. Sixth image is a matter of preference. You may leave it as is, or put the blue balloon on top of the clear post, or/and screw the back of the mushroom onto the red plastic as it was by factory (which I don't recommend). You may need to tweak the "mushroom" plastic if the ball gets stuck before it hits the disc.

PS: I apologize for the dirty playfield in the pictures, I have a new repro playfield and completely restored game now but I haven't taken any photos of my restored game yet

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