ref your questions - for many of these details we do not have good studies to draw on
but a few items that may be of help
all babesia treatments currently used are basically borrowed from malaria treatment - with v little independent work done specifically on human babesiosis. especially chronic babesiosis - as in most countries it is regarded as a small problem affecting only persons with immuno-suppression
babesia are both blood borne single celled animals ( not bacteria or viruses etc ) from the family Babesiidae, order Piroplasmida (phylum Apicomplexa) and is closely related to Plasmodium ( the organism that causes malaria), Theileria and Cytauxzoon.
although closely related in terms of lineage - in the world of microbes - there are often significant differences between related families - and this is where the challenges arise in grandfathering over therapies - as its often not know exactly how the drugs work on any one species - or if species withing families share teh same mechanism on which the drugs act
for this reason there is a lot of trial and error
malaria ( at least the strains that have not yet acquired genetic mutations that endow resistance to it) are extremely sensitive to artemisinin - however there is some work suggesting that babesia is not dependent on the same main pathway that artemisinins impact in Plasmodium.
that doesn't mean that artemisinins are not useful in babesia - they also have some activity against borrelia persisters and likely other microbes - just that Babesia is not thought to be as sensitive to it as some plasmodium strains are.
in any case there is as yet no single drug that is sufficiently active to combat chronic babesia / or malaria as a monotherapy - and 2 or 3 drugs are commonly used
1, to combat different life stages of the organism
2, to try to delay the global development / spread of resistance genes in malaria
similarly in babesia treatment - multiple agents that each have some activity - are used in combination to target synergistic overall effect
so atovaquone may be used with a traditional antibiotic - and artemisinin or Coartem added
other pieces of info that may be of use:
there is a relatively new antimalarial drug Tafenoquine being used in babesia treatment that is showing some encouraging results
also
there are one or two doctors who specialize in babesia treatment - eg Dr Lindner - website below
he advocates and emphasises the need to fibrinolytic agents to break up the fibrin deposits that protect the organism from the immune system - eg lumbrokinase - alongside anti-malarials
its well worth reading his section on chronic babesiosis if you believe you are dealing with this
https://www.hormonerestoration.com/chronic-babesiosis.htmli hope its of some help