Mackie 1640i with Thunderbolt 3 Macbook Pro

I have a Mackie Onyx 1640i mixer with FireWire audio interface built in. Love it. I need to run the latest version of OSX and Logic Pro so need to buy a new MacBook Pro. Has anyone tried using a thunderbolt 3 to 2 converter with a thunderbolt 3 to FireWire converter? Will it work? Will there be a performance bump and better latency or will FireWire limit performance. Lastly, is there anyway to upgrade the desks FireWire to thunderbolt 3? I love my Mackie desk but not sure what to do! Thanks peeps!