How detailed can the definitions be in the Order Entry module? We are planning to separate the name fields into First and Last for example.

I do not understand this question. In order to import orders into Order Entry, you must create a file with the fields in the order and format as specified in the import template. Download the OrderEntry demo and take a look.

Adagio OLEDB is capable of reading from your client's ACCPAC Plus data. If you install OLEDB and link it to MS SQLServer, you can just communicate with it through MS SQL. OLEDB is READ ONLY though.