What kind of wired access point should I get to connect to my xfinity gateway?

@XfinityEricB​ As I said in the original post, this will be a home setting.  I have ordered an Xfinity XFi gateway/router to bring the internet into the house and provide wifi.  However, the house is somewhat spread out so it may be difficult to get quality wifi throughout.  The goal is to have ONE wifi/network that can be seamlessly accessed throughout the house.

In lieu of plug-in boosters, the builder of the new home suggested wiring WAP access spots on the CEILING in areas farther away from where the XFi gateway router will be.  My understanding is that there are WIRED access boosters/pucks that connect into the internet wired into the ceiling and can be powered through that without needing an outlet.  I think that's called POE?

I have no idea if the Xfinity XFi gateway/router has a switch.  That's why I'm posting in the Xfinity community.  Most general advice asks that same question and I don't know. 

@user_b7a937 an Xfinity modem is going to have four Ethernet ports on the back of it. If you want to use a switch that uses POE that's typically possible but setting up this type of equipment is beyond our demarcation for support. It's hard to imagine a relatively new switch not working with a new Xfinity modem. I think the key is installing the modem in the best possible spot in your home and confirming the modem is providing internet. After that you can set your switch up or try to the wired access point that came with your home. 

@user_b7a937​  Xfinity gateways (most gateways, and most Ethernet routers) do not support PoE (power over Ethernet).  That's OK though.  Some  access points that support PoE come with a wall wart power adapter and little connector with two ports -- check that before you buy them.  Unpowered port goes to the gateway, powered port goes to the access point.  That's great for one Access Point.  For multiple access points, buy a PoE switch.  A cheap 8 port unmanaged power over Ethernet switch goes for $50-$60.

Can you set the same SSID, security and password for multiple Access Points so clients can Multi-Roam between access points.  Sure.  How well that works when you are walking around the house depends on the client or device firmware/software.  Some devices will stick with the AP they are connected to until that signal is gone, then will switch to another AP.  Some will stick with the one they connected to until there's a better signal, then switch.  Phones do it a bit better usually and you might not even notice when it happens.  Most of the time, you aren't pacing around the house while pulling internet data at the same time so it doesn't matter much.  Commercial gear with WiFi AP management does this better, but it's expensive and overkill for a house.

How well do 3rd party multiple access points work with Xfinity's gear?  Unknown/unsupported.  Xfinity rentals are the yugo of networking gear you pay $14-16/month for.  You might consider a 3rd party straight cable modem and Ethernet router or firewall appliance since you are doing the WiFi with access points anyway.  You'll break even at some point on cost and actually have control over your network.

If the wiring is done already, and pulling cables through the walls, and installing central patch panel is going to be expensive, WiFi Mesh networks with multiple access points can do it too.  If the sheetrock isn't up yet, you can never have too many power outlets or Ethernet jacks with a central patch panel in a new build.  

Thank you for the thorough explanations @flatlander3!!  The house is 99% done so what's wired is what's wired.  Sounds like I'll have to experiment a bit if I can't find a local tech guru to help me on site.  

If I get a switch.  Where would it go?  In the main cable box (kinda like a fuse box but for the cable/tv wires) before the juice even gets to the gateway/router?  Or somehow coming out of the gateway/router?

You would connect 1 ethernet cable from the main gateway to the switch to get the service to the device. They normally use a plug in for power, but from what you described it sounds like the current ones are wired directly into the home power. You could do this, but you could also find spots with outlets to save some time. Our Xfi pods would also be helpful for more WiFi coverage in the home for devices you don't plan to hardwire int the switch.