I have a scenario where an EDI x12 Invoice file is picked up by an OrchA and is saved to SQL Database.

Depending on the notification(if flag update sets to 1), Orch B is directly binded and subscribes the Message from Database.

So, I want to track at Port levels i.e Send and Receive and withinOrch A and Orch B when subscribes and sends out.

Can all this be done in one Activity?  Which would be a good approach TPE or BAM

You can certainly do this with one activity if it makes sense for your monitoring requirements (one business activity?).  You may need to use continuation to implement unless you include that activity ID in your SQL database. You can read more about continuation here: http://msdn.microsoft.com/en-us/library/aa559916(v=bts.80).aspx.  Note that there are a few good examples of using BAM (including continuations) in the BizTalk SDK.  

The TPE will work for most basic scenarios, but you should consider whether your current or future plans involve designs that will not work with the TPE.  Sandro Pereira lists some of them here: http://sandroaspbiztalkblog.wordpress.com/2010/08/20/bam-%E2%80%93-limitation-of-tracking-profile-editor-tpe/.  If you have any doubts, I would use the BAM API.  It requires an understanding of the BAM architecture (like the different types of streams), but is not really that hard to work with.

Can I use same Activity Name for using TPE at ports and APIs within Orchestration within One Activity ( same name).

If so, Do I need to give ContinuationID in TPE for Receive Ports and Send ports to appear in same line on portal.

And in BAM APIs in Orch, can I mention same Activity Name that given for TPE ? as I want to see everything will be in one flow in one line on BAM Portal.

You can use update an activity using a combination of TPE and BAM API.  It requires an understanding of TPE continuation ID's.  See this blog post: http://blogs.msdn.com/b/keithlim/archive/2006/02/08/527227.aspx

Another alternative is to create custom pipeline components that update the activity using the BAM API.  This way you can stick to one method (BAM API).

Walter