<p>The only reason it looks hectic is that you are assuming he will be retaking the SAT in March (optional) of junior year and that he will be sitting for 4/5 AP exams in May. Plus two more SATIIs. Much of the scenario depends on how well he does on the exams, and if SATIIs are required by the colleges to which he will want to apply.
If he wants to take a SATII besides math, he could go for US History and English. If he feels he did well on the language AP exams, he could take the SATII in one of the languages. I've read that scoring of the Spanish exam is very rigorous, probably because of the many native speakers. Latin might be easier to score high on. At Harvard, a score of 600+ in a SATII language exam or a 5 on the AP will exempt a student of the foreign language requirement.</p>