Yes, but WITHOUT Delete orders, because when you will load again the XML File, CAT will call the Exchange API to find the orders inside the XML file.

About the Date, i think that sometimes there are errors on the API Response CALL.
Data are usually returned as a long value representing che milliseconds passed from a static date (like 01.01.1950). CAT only performs a conversion to YYYY-MM-DD HH:MM:SS Format.
This is an error but nothing more than a presentation error, you algorithms/gains are not affected by that.