1. Do the licenseuuid and sessionuuid tokens expire, or are they unlimited?

Tokens expire after 60 days of non-use.

2. Is modifiedTimestamp set the same as createdTimestamp when a record is created (rather than null)?

They are both set when the record is created and the versionNumber is set to 0. Subsequent changes update the modifiedTimestamp and the versionNumber.

3. Are there any API restrictions such as calls per minute/download or size/IP whitelisting? 

The Rate Limiting is 10 requests per second. We don’t place limits on download size and we don’t whitelist IP addresses.

4. Does every entity in the data model have a UUID (as in, all records can be uniquely identified)?

Every entity has a UUID.