Seating/sleeping wise, none as far as i'm aware.Most available information is about the T6, but perhaps there are no major differences between the T5 and T6 regarding the interior?
The Beach model comes with either a 2 seater rear bench, or a 3 seater: making them 4 or 5 seaters. You can then add 2 additional single seats (swivel and fold and lift out) which are much cheaper to buy when ordering the van. They form a middle row.
They are very heavy to lift in and out. Others here can tell you (or point you to threads) where the possibility to still use the bed is discussed.
Single seats, swivel or fixed are not so heavy. One person easy IN / OUT. I use them in current T5 multilane with six single seats.
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