Lowrance HDS Gen 3 vs HDS Live Transducer

I recently purchased a 2016 boat that has two hds 9 gen 3's linked (console and bow).   I don't fully understand everything but it appears that they were set up with the y splitter and for a "thru the hull" transducer for 2d sonar and then a side scan/down scan transducer on the bottom of the jack plate.  The reason i assume this is that i get 2d sonar while on plane but not downscan/side scan. 

1)So i guess my first question is "based on what i have described, is my assumption correct that there are two transducers"?

2)My second question involves a possible upgrade.  If i were to upgrade to an hds live, would the new unit use the same transducers or would i need to upgrade them in order to take advantage of the better screen and newer technology of the hds live's.  Not interested in the lowrance live as i plan to go with garmin for that.  Just looking of better resolution for down scan side scan. 

I hope all this makes sense.

Thanks!