Jimide Medatanai Watashi wa, Kyou de Owari ni Shimasu (villainess story)

I think you should take out the better part and just leave it with "poor man's version of Schneider," other than that I completely agree with you. That moment where Evans first meets "Lana" - I can tell from his face he became completely infatuated. Which made the MC annoyed and disgusted. I can almost read her mind. "You're SUCH A SUCKER for a good looking face." 

So reading these spoilers more, supposedly the Grandfather wasn't "so bad and really cared about her" but, I don't fucking buy it or care.... he's a piece of shit that treated her poorly. Should have died then and there. 

Yeah that just makes me hate him more. You really have to suspend your belief in order to buy that a kingdom is run by idiots like these 

The cook of the inn 

Whoa.. calm down there.. XD
Actually, i say that "Shin has a higher chance becoming the ML" is because he's exactly fits those categories you just wrote as "ML material" (except money.. he still has no money.. rip)

If you see my previous spoilers, then you'll see that
Spoiler: Why i think Shin is MLin one of Shin's previous life, he's related to the temple (which is, idk why since i didn't read it fully, became the core point of the current arc).
In this life, Shin and Taki are not just a regular commoner. They can use magic and both of them are actually Princes. It's just their kingdom has fallen (i think), and they're kind of trying to revive it in the current arc.
And talking about childhood friends, Shin indeed have known Lana from previous lifes, but in the current life, the childhood friends are actually the prince and that knight (i forgot his name www).Although I think I'm ok with whoever Lana ends up with, i too, do kind of leaning towards Shin. Just because. Lol XD

So except the current arc isn't the last arc and the author have some other ML development in mind, Shin does have the upper hand as ML. 

There's a low possibility it is like that,, ;-;
Since ALWAYS, the ML is someone with money &/or status.
And most of the time, the looser is childhood friend (here both ML materials are childhood friend, but Shin(?) knows her longer, so lets name him the childhood friendo )
It really is pissing me off

I want him to win, but probably most of the readers of course will want the Prince to win, since he have status & money, and he was poisoned  before, doesn't matter that Shin lost his family, and his bro is deathly sick, and they live on poverty becc Shin thied to buy some medicine for his bro, doesn't matter that in their previous life he tried to rescue Lana, doesn't matter that he gave up his life for trying to save her.
None of this matters,

what matters is that the Prince is handsome, have status, some power, and MONEY.

I'M REEEALLY ANGRY RN

good night
gute naht
dobranoc
bonne nuit
cпокойной ночи 

so correct me if i am wrong, about Sandra's past..

She originally was a kind child though there was some issue as she was plain considering that her parents are good looking especially her mother who was a beauty. This became a source of rumor but she was loved by her parents, she was constantly being reassured of her mother that she really was their child. So although she was being showered with love and affection, she still decided to avoid looking at mirrors due to her inferiority complex on her looks.

Then she found a weak fairy. Unfortunately it was an exiled fairy, this fairy's are exiled due to corruption and they die later. Iirc, another fairy felt sorry for those exiled and helped it w/c at the later chapters made the "fairy king" think more on how to handle exiles to avoid this thing happening. So what happened was, Sandra found the fairy, thereby saving it from death however as a corrupted fairy it went inside Sandra and corrupted her thus feeding her inferiority complex more. Somehow, i don't remember how anymore, but it was actually her biological mother who was her first victim. With the fairy's influence she began to resent her mother for not "passing" her beauty to her and, i forgot, she somehow managed to "absorb" her mother's beauty causing the mother to fall ill then die. In the course of this, you can see Sandra rejoicing on her beauty. Then the rest of the history happened, which was absorbing the beauty of people that made them ill. This happened in the temple too that was why many priests are willing to cooperate with MC.

Iirc, it was the fairy king that has the power to purify the corruption on Sandra. I am not sure if MC and the fairy king has contract or something, or if the king shares/gives the power to MC to purify the miasma.

This are all what i understand using mtl so feel free to correct me. 

I dont think grandpa abused her, He just told her women are not supposed to stand out. Other than that he didn't do anything else. As for the people who said that he is strict for no reason, overprotective parents are usually strict. Its not for no reason. As some previous comments had explained, the grandpa most likely lost his confidence to the royalty and lets her live as a commoner instead for her safety as its much more safe for her. I dont get why hate him when he is one of the most realistic representation of a parent there is. The 'heroine' was not on her right mind because she was corrupted by the fairy. Its not that we have to feel bad for her, its just that they gave an explanation to her evilness. The prince made sealed her memory cuz he is afraid that the people who wanna kill him would go after her. I dunno about the shitty prince, he should die as he is the only fucker here along with evan. At least for me