Modem upgrade question - finally switching to Xfinity: Wi-Fi disableable? can I reserve IPs?

Have old style cable boxes (with cable connections), never got onto ignite.

Finally now switching to the new Xfinity boxes, so I am awaiting delivery of replacement modem and a few Xfinitiy boxes: do not know model of Xfinity box I will get (will be 250 MB/s service).

VERY SIMPLY - Will I be able to configure new gateway modem the same as current modem?
Specifically:

1. Can I use the same 192.168.0... (/24) subnet I use today?
2. Can I disable the built-in Wi-Fi (already have three Unifi Access Points, don't want Rogers Wi-Fi)?
3. Can I reserve specific IP addresses on my local LAN like I do today for several devices?

Hopefully all the above are possible without losing any functionality!?