Is an agreement to purchase goods for the company for a specific amount, with a pre-determined profit added after a certain period, and then transforming that into a sale to the company after the purchase, as if the seller sold it to the buyer with an increased profit, considered Murabaha or Riba (usury)?

Your agreement with a person that they give you money to buy goods, then they bring them to you and you pay them interest, has details:

If they give you the money to buy the goods you desire, and they bear the profit, loss, and guarantee for them, then they sell them to you at an increased price, this is a permissible murabaha (cost-plus sale). It is preferable that you do not undertake the purchase of the item for them, but rather they appoint someone else to do so.

However, if the intention is that they give you the price, and you buy the goods for yourself, and they only transport them to you, then you repay them the amount with an increase, this is a usurious loan which is forbidden. They must first own the goods, then sell them to you.