Question:

Does the 5520-VIM-4YE support 1G connections along with 10G and 25G?

Answer:

No. The 5520-VIM-4YE only supports 10G and 25G port speeds. If 1G and 10G is required you can use the 5520-VIM-4XE instead.

Note:

In Fabric Engine, you must use the sys vim-speed command to set the speed to 10G or
25G for 5520-VIM-4YE. The default is 25G. A reboot is not necessary after setting the speed.
In Switch Engine, use the configure ports partition command with 4×25 or 4×10.

Example,  for 5520-48p with 5520-VIM-4YE

configure ports partition 57 4x10G

The show ports partition-template command will confirm configuration in place.