I'm confused because the tips and notes don't say anything about the subjunctive being used for ''have to''?
Yeah, bad translation. It's more like "should", "ought to", "may s/he ...", "let's ... ", "shall we... " etc. "Have to" is usually translated with lazima and the subjunctive.
So this whole lesson is actually wrong? hm.
Wow that is indeed... hmmm
For a while yes, everything is out of sense. And " Tips and notes " writes avout the form "must" or " have to".