I am sampling in short audio clips from a VST( guitar strums) to loop through the sequencer. I am bringing them in pretty raw (without reverb or compressors) and want to use the much higher quality motif effects. Do I need to insert these effects upfront when I record, or could I simply add then later in the signal path when I edit my voice and mix?

You can sample through the effects if the incoming signal arrives via the A/D Input and/or you can add the effects later, it's really your choice.

If I am only looking to add reverb and a compressor to a guitar, can I add them later with the same sound result?

Yes. It is possible.

It would seem to give me more flexibility to add later rather than record insert it into the sample, no?

That is certainly true in some cases, in others not so much. "Your mileage will vary!" is the expression that best states it. If the effect is a crunch guitar distortion, and Wah-Wah, there are absolute benefits to record through the effect... you are likely to perform differently under those circumstances. Note duration means that a whole note with distortion has an entirely different attitude that the same note without. Playing *with* the Wah pedal is certainly different than it would be adding it after the fact. But sometimes it's not so dramatic a difference.

What other differences, pros/cons ? Can I choose from the same compressors / reverb at Insertion vs later? To simply add these effects to a strumming guitar sample, will it sound better to add to sooner vs later in the signal path?

The beauty of it is since you have a choice is you can try it both ways and determine your own best workflow.

Once you create the sample Waveform, you can CONVERT it to a Motif ES Voice... which allows you to treat it with its own dual Insertion Effects, Sends to both the Reverb and Chorus processor. You can treat it with all the features of a ES VOICE. PART EQ, Filter, etc., etc., etc.