All properties are checked in simple search unless search profile is defined and search is restricted to set of properties.
User Defined Property appears in advanced search as searchable if there is value defined on it. Can be set in set properties dialog.
Dynamic property is a simple <name, value> pair - the support in UI is very minimal. In contrast UDPs have more metadata on them -better UI support, can appear on diagram with own color.
At the end dynamic properties and UDPs are stored in the same way, for scripting they are get/set in the same way.
Thanks, Philip. I created a user defined property, IsReference, for Entity and Table with list values, true and false, and it works great.