Good question, and I'm curious what the experts say. Surely it depends on the software that handles DHCP.
I've always set static addresses in the DHCP address range and it has always been reserved and never assigned to other devices. I've used ASUS and MikroTik for what it's worth.
If you're the type to set static addresses on the devices themselves, then that would certainly increase the risk of a conflict if it's inside the address range.
There are two types, CMR and SMR. You can read online about the differences. CMR is better because SMR tries to be all fancy in order to increase capacity, but at the cost of speed and data integrity.
It won't be front and center in the specs of a particular drive, but you usually find the info somewhere.
I wouldn't worry about higher capacity failing sooner. If you have 10x4TB vs 2x20TB, that's 5x as many drives to go bad. So a 20TB drive would need a 5x worse fail rate to be considered worse. A pro of larger (fewer) drives is lower power consumption. 5-10 watts per drive doesn't sound like much, but it adds up.