Seeking Feedback on Motorhome Lithium Battery Conversion Plan

I’m planning to convert my system to lithium batteries and would appreciate any feedback on my approach. I’ve read many helpful comments here about battery upgrades.

My Plan:

  1. Replace existing Lead Acid house batteries with 300Ah lithium battery bank

  2. Retain existing PD9100 Lead Acid Converter, B.I.R.D., and Emergency Start Relay (though I don’t intend to use the Emergency Start function with lithium, so I may disconnect it)

  3. Install an Orion XS DC-DC Battery Chargers directly before the house batteries (see diagram)

Specific Questions:

  1. Charging setup: It seems the DC-to-DC charger alone should be able to fully charge the lithium batteries, even with my older converter. I don’t see why I would need both a DC-to-DC charger AND a lithium-specific AC-to-DC converter. Am I missing something?

  2. Existing components: I’m hesitant to remove or modify the B.I.R.D. and solenoid. Is there any harm in leaving them in place as-is?

Thank you in advance for your advice!