About the two stars player, his quality is same as the level you are in. I.e. I am at level three my two star layer will be between 16 & 20 quality.

He will be 4* for level one manager and and 3* for level two manager.

If you buy the token player at the start of the season he will have high chance to develop and gain another star. His value is between 3 to 4 million so it will be like an investment. (if you take a loan from the bank it will cost you the 24 tokens)

Any player you buy when you have full squad will leave the club after one week if you fail to sign him within the week limit.

I usually buy both at the start sell the two stars and keep the 4* till the end of the season and sell at 4 or 5 millions.