Hi,
Unfortunatly, Parse do not expose any api to get information of existing classes descriptions, so I can't know or query Parse to know what class, fields and types the current account has...
If you know a way, I would be delighted to implement it ( as I can in DataMaker when querying Sqlite with the pragma queries)
can you elaborate on why you would want to give a unique Object ID yourself? I would not recommend this, because I am involved in some IOS native development and the IOS sdk from parse do not like you messing with class objectID, especially when you starting using cache, and offline use.
If you want your own Unique ID for entries, one option would be to simply create a new entry and leave the ObjectID built in field be managed by parse automatically.
bye,
Jean