I can sense your panic but there is no need to stress. Stress attracts sha so let's not go there.
It can be difficult to adhere to feng shui principles in a structure that was designed without consideration of such. It's like shoving a square peg into a round hole.
So, regardless of what a bagua map might suggest, please don't force anything into a specific place if the result is an unnatural placement of furniture that impedes the flow of chi.
This is what feng shui is all about: good chi.
There are some office basics however.
1. The person who holds the top position should be furthest from the door. This means that by-passers and clients will not interrupt or bother him. They will be met by underlings first who can screen those whom will be seen by the CEO. Your time and attention are valuable and you do not want to waste your energy on just anyone (salespeople, delivery people, etc.).
2. If this is the Relationship corner, that is not a bad thing. The CEO really is a relationship person. Success really is all about good relationships both inside and outside the office. Harmonious and mutually beneficial relationships mean money to the company.
3. Having an underling in the Prosperity corner is a good thing, too, because he/she will bring in prosperity to the company. Remember this is an office (of the business) and not his/her personal living space. Just be sure this employee has a well-functioning desk area. No clutter. Stream-lined for efficiency and few personal effects upon the walls.
4. Part-time employees. Hmmm. They will come and go and could potentially take with them any prosperity. Be sure to treat them well and invite them to return. Place a wall sign or logo of the company in their desk area to "anchor" the business to that area and thus, any money can comes into the company will stay there.
5. Keep the furniture arrangement very pleasing to the eye and with easy access as one walks through the room. No tight corners, doors banging into each other, blocked entries or exits. No risk of banging one's knees into desks, etc. If YOU can move with ease, the chi will flow with ease.
Keep the atmosphere bright, clean, airy and sweet-smelling. Remember to use coin-shaped leafed green plants! A small water feature would be great, too, but nothing that would take arduous time and labor such as an aquarium.
Good luck and great success to you!