4 signatures in total, have no idea who they are. Glove appears to be vintages

I found this hat at an estate sale in WA state. The front of the hat just says “umpire” (pic posted in comments). Of course It could just be somebody random/local but I thought I’d ask here! Appreciate any help :)

Front side more likely than not is Jon Brockman but having a hard time figuring out the back side. pls help!

Found a signed jumbo card from invincible comic on eBay by Dylan Fuller…can’t find any info on who this person is. Any help?

I have this vintage 1998 DEKRA Ferrari cap from Michael Schumacher's collection, but I'm trying to figure out whose autograph is actually on the brim.

​It looks like it says "A. Sch...", but I'd love to get a second opinion from people who know F1 memorabilia or handwriting analysis. Does anyone recognize this signature? Any thoughts or insights would be awesome!

In my opinion, it's definitely not Schumacher's signature it looks nothing like it, unless he signed it quickly but it still doesn't have his initials.

Helping my neighbor! She said her mom went to some sort of HOF celebration that had autograph tables. I don’t need to know every auto, just curious if any cool or unique players here. I don’t have any info on where or when this took place, but do know they are real. It belonged to elderly neighbor and is now in possession of her daughter. Thank you all in advance!