You've probably read the various schools of thought regarding battery bank composition, but it seems that for most situations, it works OK to have deep-cycle batteries (like those AGMs) only, instead of (one) deep-cycle for house use and a high-CCA battery for starting. Either battery type can serve in the opposite role if necessary. Since you're not off-the-grid much, it probably doesn't matter what sorts of batteries you have - an all-AGM deep-cycle bank should be fine.
If you later want to add a high-CCA battery just for starting (and brief high-load use, like for a windlass), you might be able to move one of the AGM house batteries to the compartment under the forward-facing port side settee bench - I think we can run cables to/from there to the main battery box, through the cupboard under the nav table: e.g., to hook up the 2 AGMs in series.