How to connect two Ethernet switch ICs together using MII Interface
Q1: It's difficult to say with only the datasheet. There might be application notes about this. If you want the largest amount of RJ45 copper PHY ports, P4 should be left with UTP, so port 5 is available for MII. As you can see, the MAC5 can be set to MAC mode MII or PHY mode MII. So either they both should be in MAC mode with crossover connection, or maybe one in MAC mode and other in PHY mode. But it all depends on the details how it works in MAC and PHY mode.
Q2: If direct crossover with MII connection is not possible, you can add a PHY chip with MII connection to both chips for an extra copper PHY port between them, and it should be possible to connect them together without the magnetics. Most PHY chips have datasheets and application notes to describe if they support transformerless operation and if they suppport a DC coupled link or AC coupled link.