@Ysam,

CPEs are outdoor devices with directional antennas, which are used pair-wise to create wireless links over very long ranges (kilometers).

EAP225 are indoor APs with omnidirectional antennas, which have a much shorter range. Note that with EAP225-Outdoor and the mesh network function it is also possible to create a »bridge« (I prefer the term »wireless link«) between two distant locations by using a pair of EAP225-Outdoor. In this case you need Omada Controller to set up the mesh.

With both types of devices it is possible to link a network of multiple wired PCs to a remote LAN.

Note that there must be a free line of sight between the two APs no matter which models you use.

To give a recommendation of the devices which fit best to your scenario we need to know more details:

• What is the distance (in meters) of the locations to link together?
• What throughput do you expect at least?

Technically it's possible to link a CPE220 to an EAP225-Outdoor, but then the maximum range is that of an EAP225-Outdoor.

Ysam wrote

In this situation, I am not sure if another EAP225 outdoor will support this scenario.
  -EAP225(main AP) + EAP225(secondary via mesh) connects to my old router via ethernet cable to provide internet to PCs?

Yes, this works.

  -EAP225(main AP) + CPE220 connects to my old router via ethernet cable to provide internet to PCs?

Could work, but not recommended. Omnidirectional signal from EAP225-Outdoor will be too weak, throughput too low.

2x CPE220 will work reliably up to 100 Mbps Ethernet throughput.

100+ meters if I am behind walls but outside around 80 meters.

 

For 80/100m I would try a mesh solution, 2x EAP225-Outdoor mounted outdoors, free line of sight (no obstacles in-between).