Actually I think your description is more than a bit ridiculous. When he was found with the glass breaking hammer it was in a back pack that was large enough to also contain a large kitchen knife, 2 phones and a laptop computer among other small items. So, he was known to carry such a pack when breaking and entering.
Re: the 2 knives. My understanding is that the idea of 2 knives comes only from trying to fit Raffaele's large kitchen knife into the story, because some of the wounds could ONLY have been caused by a smaller knife; and in reality the smaller knife could have caused ALL the wounds.
If he was wearing this backpack, why do you suppose he hadn't starting packing some of Filomenas things in it before leaving her room?