Yes it is safe to have them shipped as long as the person you're buying them from knows what they are doing. Make sure they insulate the box and provide a 72 hour heat pack. Make sure to ask questions from the seller, if they aren't answering them I would suggest switching to someone on here.
Excel will work much better on the HC if you inject it directly into the substrate instead of dumping it into the water column. I recently ordered a 9" needle and syringe combo to do the trick. I'll be uploading some photos tomorrow if you'd like to see what they look like!
When the DW is done soaking you should lay that out first. Generally it will provide a good transition from your carpet plant to taller plants (unless you just stick the DW straight into the tank vertically haha). But if you can arrange the DW first it might be easier to help you with plant ideas. I would recommend not making a trip to the LFS for plants until you plan the scape with the DW. But you seem to be a little sick of DW :P
K, will CRS be ok with the excel? Should I turn down the dosage to like 1/2 or so?
Yea the driftwood's been soaking for about a week and none of the pieces are sinking yet! And they're pretty small too!