Gigabit Ethernet Interface (via Marvell 88E1111) with Cyclone IVE FPGA

Yes the core should be good for the job. It does requires an extra license so it isn't free.

Are you using a development kit? If so you should already have an example design with the TSE Mac that you can look at.

If you are making your own board I would strongly suggest to consider alternatives to the Marvell PHY because Marvell is very annoying with the way they handle datasheets. They require you to sign a restrictive NDA before sending you any documentation.