I'm pretty sure browsers will always detect my Surface as a device with an accurate pointing device, which is not how I use it most of the time, so I doubt the API is reliable. Also, according to caniuse.com, Firefox doesn't support it.
I don't know if they still have those screens though - those pages got discontinued last year.
They probably use a smartphone app now. (One of my friends is a traffic controller at ProRail, and if I’m over at his place and there’s some question about whether the trains run on time, he checks his phone. I’ve never looked, so it could be be just uses the NS app, but I get the impression he has access to more info than that provides.)
Are there issues that could be fixed by disabling the DHCP server setting in the routers and connecting the modem to their WAN ports instead?
Either/or; not both.
If you connect your routers' WAN ports to your modem, then you'll typically be adding another layer of NAT at the router; even if you're not doing that, you'll be creating a subnet for each router's clients that will be separate from the subnet between the router and the modem.
DHCP is a broadcast-based protocol, and broadcasts don't cross routers. So if you reconfigure your routers as above and turn off their own DHCP, clients that connect to those routers won't automatically get IP addresses assigned to them; the upstream DHCP server inside the modem will be visible only to the WAN ports on the routers.
Assuming the only reason you have these routers is to provide wifi service on your LAN - that is, assuming that what you actually want to create is a single subnet with all your (and your neighbor's) Ethernet and Wifi devices visible to each other and able to access the Internet using the modem as their gateway - then what you need to do is turn off the wifi routers' routing brains and set them up as straightforward WAPs. This is the simplest configuration that could possibly work, and it means that the only routing device whose settings you then have to worry about will be the one built into the modem. Also, all connected clients (including the WAPs, unless you configure them with static IP addresses which is probably a good idea) will then be in the same subnet, able to read and write broadcast traffic to that subnet, and will therefore be able to get IP addresses from the modem's DHCP server.
Better routers will have explicit settings that let you do this, after applying which you will find that the WAP's WAN port works just like another LAN port. If you have shit-grade wifi routers, your best bet is simply to turn off their own DHCP and wire them to the modem via one of their LAN ports.
If you actually want you and your neighbor not to be able to see each other's devices on the same LAN subnet, that's when you'd use the configuration with a separate wifi router for each household, each connected to the modem via the wifi router's WAN port and all three devices running their own DHCP servers. The routers would then pick up IP addresses for their WAN sides from the modem's DHCP server, and clients in each building would get IP addresses from the DHCP server inside that household's wifi router.
If you're going that way, you'd want to connect nothing to the modem but WAN ports from wifi routers.