This behaviour is controlled by the eval-expression-print-maximum-character variable.
eval-expression-print-maximum-character is a variable defined in `simple.el'.
Its value is 2305843009213693951
Original value was 127
Probably introduced at or before Emacs version 26.1.
The largest integer that will be displayed as a character.
Your main confusion lies in that ^L isn't a two-characters regexp, it's an ASCII control character (page-break/ FORM FEED), that's why it appears in red in your system.
on #3, if you iterate over the blanks and using M-x describe-char you'll notice that it should match either space or tab. Reasons are described in the documentation string:
Regexp for ...