1. Is whole house surge protection at the panel effective and worthwhile?
Yes. Some of it can be very cheap. Panel makers have a variety of units that fit in like breakers. Utility companies also offer protection at the meter. They usually recommend an additional surge protector near anything sensitive though, as the EM pulse from lightning may induce a surge directly into house wiring.
2.
Apparently cable and phone line protection is separate and must be
added to the panel protection. I assume this is appropriate to add if
going for whole house protection?
Yep, but it depends on whether you can afford this. Having a surge protector bonded to ground at the service panel is the best way to go for any outside copper, including roof mounted antennas (TV, Satellite), etc. It is the gold standard. However, there are also great units from Furman which include all of this in one.
So my usual advice is, get protection at the service entrance, and a Furman at your sensitive electronic devices.
3. The realtor ask about
adding a generator. I assume that is a separate issue to provide
temporary power during an outage but does not offer line surge
protection, correct?
Right, it won't protect you from a surge, but it will keep your refrigerator working. :)