I have some questions regarding some things in Re:zero

Recently I've been writing Re:Zero fanfiction, and with that I've started to wonder about a lot of thing in the Re:Zero world that just don't have clear answers online, so I decided I'll just ask them in this reddit post.

1st- How do people in the Re:Zero world know what's a sea? There are no seas in the world, only rivers and lakes.(I do remember the Augria Sand Dunes being described as 'an andless SEA of sand', so they know what a sea is, though maybe it was Subaru who said that, still weird that Anastasia, for example, didn't question it)

2nd- Still in the sea tangent, how has the White Whale recived it's name? Whales are sea creatures, and there are no seas, so there are no whales, which means the white whale is the ONLY whale in the world, and it just gets worse if the word 'whale' was exclusively created to define the white whale, since the addition of the characteristic 'white' in it's name implies that there are whales who are not white.(To be clear, I do understand the storytelling reason for it to ble called the white whale, since having a living catastrophe called just 'whale' would be very underwhelming, but there isn't a lore reason for it to be the case, and thats the cern of my question) Daphne's name for it as 'Big Fishie' is actually more lore accurate.

3rd- How do the people in the Rezero world have the concept of an hour, minute and second? Their clocks are divided into 4 sections of 6 hours each, but that's translating to OUR worlds way of measuring time, in the rezero world time should only be measured in wind, fire, water and earth time, so how do they have the concept of an hour? And, if they have hours and just choose to use a different clock for cultural reasons, then why aren't there 24 hour clocks in other parts of the world that don't share the same culture? Why doesn't the 24 hour clock exist?? It's objectively more accurate than a clock divided in 4 and would be sought out for merchants scheduling deadlines, for example.

4th- Is there any reason whatsoever for we to don't have the year in which Rezero happens? The timeline in the wiki is measured by before and after Subaru gets Isekai'd.

5th- Still on the subject of time, how do months in Re:Zero work? How many are there in a year? How many days are in each one of them? I know some of them have revealed names(I think) but I'm not too sure.(also, if months in rezero have 30 days like in our world, would they have leap years? Or is their calendar like the one in middle ages in the sense that it's a bit off? If it's the second option, how many days would be off in the rezero calendar??)

6th- How many years exactly has it been since Satella was sealed? We know the '400 years' thing is approximate, since after the one year timeskip they still say she was sealed 400 years ago, not 401.

7th- I need a genuine reason as to why subserviance collars aren't being used in or Roy.

8th- How Emilia had access to purple dye when little? Even in the modern world the color purple could only be widely obtained little time ago, so how Emilia had purple clothes back then? It's implied that she wasn't rich to afford them, and the color purple is uncommon in the rezero world since basically no one uses it, so how Emilia had access to it? Purple flowers give out blue dye that fades greatly with time, while the purple in her clothes lasted aprox 100 years. Did Geuse get them? Didn't he had better things to do instead of searching for the one thing that gives the color purple????

9th- How do people know Satella was a Half-elf with amethyst eyes and silver hair if she was hidden by that shadow veil that she always wears? And how did anyone recognize it was her when all you can see is basically a giant shadow? Did her friends just decided 'let's describe her specific features to the entire world, condemning all people with similar features to a life of discrimination'???