The first 2 queries: it happened once, in the past. There's no reason to use the present perfect. Don't use have; (I don't think you really wanted to, as you put them in brackets! )
Did you miss only one out of several lessons on that day? If not, you should say 'I'm sorry [that] I missed the lesson on Monday' or 'I'm sorry [that] I missed Monday's lesson...'.
You could say 'I'm sorry to have missed...' But 'I'm sorry I missed...' is easier and clearer
You want the homework for next Monday [no 'the'].
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