Will extra rules to my diceware list generation scheme decrease security?

I finished reading the Code Book by Simon Singh, I’m interested in playing with some of the ideas in the book to help increase my own understanding. I don’t intend to implement the following in any consequential settings; I’m only interested in exploring the security implications.

I want to generate alternate diceware lists that have quirks, like each word is typed with the left hand only, or keystrokes alternating hands when typing. Assuming I can generate 7776 different strings, and am able to follow all of the other guidelines of diceware, are all diceware lists equally secure?

In the German Enigma Machine no letter could be encoded to itself (ex, a cannot be encoded to a). This detail helped crack the code. However I don’t think this applies here, the strength of the password doesn’t rely on a cipher. I don’t see why 6 or 7 strings randomly chosen from a list of 7776 wouldn’t have the same entropy, no matter the list. Theoretically, it could just consist of 7776 different binary lines couldn’t it?

I understand that additional rules to password generation sometimes decrease security. If an attacker knows my diceware list, does it matter if every entry consists of only 15 unique characters of the left hand? Is there less entropy?