Our Enterprise Architecture department is going to be deploying a new system that will integrate with several other systems we have, including Salesforce, and wants to know what limitations there are with pulling data from various objects within Salesforce. Can anyone help answer their question and/or make a suggestion as to how to give them the data they need?
Broadly, you will have two types of limitations. API limitations and Governor Limits.
The API Limits are limits imposed by Salesforce that regulate how often you can hit the API. These limits will restrict the access and depend on the type of license you have (and other factors). A list of those limits is here.
The Governor Limits are imposed by Salesforce to ensure that your work does not affect other people in the same pod. Since Salesforce is a multi-tenant environment, this is a must. You can find most of the limits here.
I am sure I am missing some things here, but I think your enterprise team will have most of what it needs in the two links above.