If a company or individual appoints a consultant to design products for them, and the company /individual invests in the IP rights, design rights, and trademarks? Is that Company/individual obligated to pay a royalty fee to the consultant?

Payment of royalties for the trademark would be mutually decided by the owner and the consultant. Normally the logo or symbols of the products are designed by the consultants. For the design, the consultant has already been paid consideration, because that was their job to do. In this case there is no need to pay royalty to them. Also, note that the value in the trademark is the “trade name or brand” created but not in the design created. However, in end, it will be the mutual agreement of parties only.

In case of copyright we need to check who is the original owner of the product and if other persons are involved in it then one has to take NOC from all of them to register under copyright.