I can't answer all your concerns. But I can say you cannot take the praziquantel with albenza and ivermectin. Praziquantel and ivermectin are not combined in any of ICU's protocols.
I don't feel certain that scratch marks are an indicator of strongyloides. I have strongyloides and I have never experienced scratch marks. Strongyloides are well-known for being invisible.
I hope other posters can help you diagnose what is happening to you. You may need to do some more research.