[The Bus Crew]

I know some of you have switched from lead acid to lithium and I am now at the do it point.   Before I make some expensive learning mistakes I was hoping you could recommend what may have worked for you. 

What I am planning on doing:  I will keep 2 lead acid 8D batteries in the back for the Detroit start batteries.  I will put 2 lithium 300ah batteries with built in battery management in the house/generator battery location. 

Future plan includes adding 8-10 300 watt solar panels.  

If you see a problem or opportunity for improvement with my plan please share.   
My needs include being able to boondock (with or without generator).

Questions :
1. I have the original converter and a newer inverter.  I understand I have to replace the converter to charge the lithium.  Do I get a converter/inverter combo or separate units?   Why?

2. I plan to install a battery trickle charger from the lithium to the lead acid.  Will this be enough to maintain the lead acid if I remove the original converter (I know the converter is for the house without merge) but if the engine start batteries die how do I charge them as I do not think I can merge if I go lead acid and lithium?

3. How do I determine the correct ratio of battery ah to solar watt capacity?

4. What am I missing?