| If the fx loop is series (not parallel, not blended/mixed) and if it has a suitable output level for driving the rack devices (this cannot be assumed) then both rack items should go in that loop. The BBE affects signal timing, so you would be better off running it last after any/all other tone shaping, per its instructions. So comp then BBE.
You still have to ask yourself which tone-shaping functions of the VAmp are important to you versus which tone-shaping functions on the Trace are important to you; and also whether you are using the VAmp to model a complete am rig tone.
What I'm getting at is you may want to bypass the preamp built into the Trace if you are getting all the amp modeling, tone shaping, and EQ you need from the VAmp. Putting two preamps in series can add noise and affect your tone negatively (sometimes). You would bypass the Trace pre by running
bass --> Vamp --> fx return jack on Trace
In that case you would fit the rack gear between the Vamp and the fx return jack.
Unsolicited opinion: Too much gadgetry, it will do more harm than good to your tone. | 
