I'm gonna include exercises for sure, but for now it's kinda too early for us to be able to do that.
is there a good textbook you can recommend?
I know this might be a bit shocking but I'd say no there ain't, because Arabic gets very little attention from the language learning industry and a lot of the material is aimed at "diplomats" wink wink, that is why I make the material myself. But when it comes to the alphabet I guess any book will do, maybe check Alif Baa Introduction to Arabic Letters and Sounds.
Edit: By material I mean the pdfs I share with my students, not these posts.
This is not a problem when your language must be written in cursive. With English, you need to learn to write in cursive, but in Arabic it's called learning how to write
Well, it seems they share the same Semitic origin, but I think the answer to your question is probably no. I don't know any Hebrew, but I know that Hebrew speakers have a hard time pronouncing ح .