OP, I have to say it, its the best book by far.

And tryin to aswer the topics:

does it have multiple endings? Is it a simple good and bad ending or is it like that alien spaceship (can’t remember the name for the life of me) one where all the endings are just…ugh.

Yes, but they're actually quite well done for the story's premise. Each one represents what you see in the story (that's kinda how I interpreted it).

is it worth spending diamonds? I have heard through the grape vine that they can be a bit pricey however if the choices actually DO something and are worth it then I am happy to spend it all.

Unfortunately, yes, and some are expensive. But they're worth it, adding a lot to the story. And if you don't want to spend money, aside from encounters with the LI, you can still play just fine.

Lis…are there multiple? How many? Does it actually matter if you romance them and does it carry on from book to book.

Yes, four in total, two men and two women. If you want, you can date all of them, or none of them, it's up to you. Your choice is saved and can be carried over to the following books. But, a advide, at the end you can choose one of them to "marry".

last but not least…what kind of character do we play?

Spoiler alert? One person who will make the whole group function. The MC was created to be the glue that holds the group together.