To correct the first part I'd say, 'the clients financial position is good (or sound or secue) and is able to meet all their obligations to the bank. (I used their obligations because if the client is a firm, we are talking about lots of people within the organisation. If it's a single individual we use their because we do not know their sex.)

This sentence is not correct: The client is very cooperative and having a good character. "The client is very cooperative and is of good character." or "The client is very cooperative and has no character issues".

Yes it is