Shimary

Depending on your definition of proper. Msin pair have a hot make out session for main pair, but its in a dream. Second pair have sex, but its shown as a flash back. Both are pretty hot (imo), but in general this show is for slow burn lovers...

oh, well... and how big is that age gap in the novel?

he probably was not a grown ass man, they just desided not to get new actor

Vier listened to the call between kidnappers and Kelvin (its the saving part he mostly missed due to being half dead), so there is no need for extra people telling Vier that Kelvin left him to kidnappers mercy. And I think Viers dad told him that Kelvin informed him about kidnapping and helped the police (but i am not 100% sure and not rewatching it).
Another thing - there is not really a person in the story that will fit your theory (close to Vier, present in both timelines, still alive, interested in breacking them up, ets). And it will be redundant to add someone like this just for what? Make Kelvin a bit more palatable?

That deal was not for "them", that was for Kelvin only even if it was a kind of joined project. But most importantly - Kelvin abandoned Vier at most crutial moment. And not only he choose not to listen to kidnappers, Vier listend to it in real time.
The fackt that he did take part in saving operation later and even regretted his actions does not negate that initial bertrayal. And Vier is a person who would have never choose buisness over a person dear to him.

for the first one - no matter what Kelvin says when kidneppers called him about Vier first time he did not drop everything to save Vier, he went on to do a buisness meeting first (it was shown clearly to us), and after that he "helped" Vier father to save Vier, but that help also led to Viers family company going near bankrupcy. It is even worse in the books.
Its possible that Kelving is not technically lying and he did risk something saving Vier, but then it was after he made sure his own plans are going smothly.

for now loophole is - all chinese cast and prodaction, but it relises as from non chinese company and goes as "forein" in mailand China - there are several shows like that already and more to come (I personaly recommend Kill to Love and To my shore)

I think it was karat cat, local breed, not European :)

Depending on your level of tolerance for last 2 episodes idiocity. The rest is pretty good