I'm not familiar with those instruments, but I've controlled MKS mass flow controllers via RS-485 from LabVIEW and found it straightforward. I think there were some VI's from MKS that used the old serial functions, but I decided to write my own driver using VISA. As long as you have the manual for the command protocol from MKS you should have no problem. If there's a setup or utility program from MKS for these instruments, use that first to verify communication and to check that the instrument settings such as serial baud rate are correct.
As for the RS-232 ports, you'll need to add extra ports using either a card or a USB adapter - both are fairly cheap and widely available. Many PC's now have only one RS-232 port, so check how many you need to add.
