Good morning dunacn
Your wife's instincts are on the mark. You shouldn't count on the dust extractor/sander combo to contain all the lead-contaminated dust or chips that will be removed. For that reason, the guidelines of EPA RRP require a multi-step approach to removing paint such as what you have in your old house.
This multi-step approach includes sealing off the work area, using appropriate tools and methods to remove the paint (flames and high temp heat guns are specifically prohibited), use of PPE by workers, certain clean up procedures to be followed afterwards (including using a HEPA vac such as a Festool dust extractor, which complies with the RRP standard) , final verification using certain testing methods, and using specified procedures to dispose of the contaminated materials and used PPE.
You are exempt from these requirements as a homeowner doing work on your residence, but with some exceptions (such as if day care if provided in the house or part of the house is rented out to tenants). If anyone is hired to do any part of this work, then it becomes a requirement to follow EPA RRP. State and local laws might require more, but not less, than EPA RRP.
So, the bottom line is that you should use your sander and CT combo, or other safe methods, but only with the other steps such as wearing PPE. There is a huge amount of information out there. If you wish to know more, start by reading all the info at the EPA's website on the RRP Program (this is not a quick and easy read). Check also to see if your state has additional requirements.