FX Sequence (or Order of Plugins)

Yes. Also note that there is a Pre/Post Prochannel button that will place the FX Bin/Rack* before or after any of the Prochannel modules (the whole strip actually). So if you want the Prochannel before the FX Bin/Rack* in your signal chain set it to "Post" (click the Post button in your Console View strip... it will turn blue) or if you want the Prochannel to come AFTER the FX Bin/Rack* set that button to "Pre" (the button in the Console View will still say Post but it will be gray instead of blue). You can hover over the PC Pre/Post button as a second verification of it's status (a little tooltip will popup by default).
 
If you need some Prochannel modules to come before and others AFTER your FX Bin/Rack* then you can create an FX Chain and insert it as an FX Chain Prochannel Module (just like you would any other Prochannel module) then move it in between the regular Prochannel effects modules you would like it to appear.
 
*I kept use the Fx Bin/Rack to describe the FX insert point because Cake changed the name of this insert point from "Bin" to "Rack" in the new Sonar. It's the same thing only they added some slight changes/improvements. To me changing the name adds a lot of confusion for no real reason and I brought it up so you can equate the two as the same thing when searching older manuals an tutorials when looking for info on such signal chain issues (and anyone else who stumbles across this post looking for the same info).
 
Also ther is a Clip FX Bin where you can insert effects directly on a clip before it hits ANYTHING.
 
The signal chain for audio essentially goes like this Audio Clip > Clip FX Bin (and the FX in the bin go from top to bottom) > Track Input (which starts at the top of the strip at the Gain Knob) > Prochannel Strip OR the FX Bin/Rack (depending on the Pre/Post status of the Prochannel) > Sends (if you have them inserted and have a pre/post fader status that doesn't affect the main output of the track but is important to understand) > Fader > Track Output > Bus (which can be the Master or any bus you want which will have it's own Prochannel and FX Bins/Racks with the same Pre Post stuff and their own output/send options).
 
Signal chain is one of the more confusing things in Sonar (and audio in general) so getting used to how it all works is pretty crucial to making things happen in a logical way.
 
It takes a while to envision the signal path but worth getting used to. IIRC there is a reasonably handy info graphic in the Reference Guide (or maybe Quick Start guide) that shows what I just described above but also includes multiple variations of outboard gear as well.
 
As far as the CORRECT way to order actual plugins... there isn't one right way. Everything effects everything else so you have to be logical about it and know what will hit what and how and how that next thing in the chain will hit the next thing in the cahin and so on.
 
More than you asked for but this is the type of title that will show up in google searches so I figured I'd elaborate.
 
Hope I dind't make any mistakes and that is a somewhat simplified signal chain.
 
Cheers.