Is it suitable to wire 'protected' li-ion cells in series and parallel? 2S6P
It doesn't look safe, no. If I read this correctly, it is 1P2S6P and it's neither cost efficient nor safe. First you connect the cells in parallel. Once you do that they become one self-balancing cell. Then put them in series. So basically 6P2S is what you need, P first, S second, and no more Ps after that. Otherwise single sells in series will drift without cell balancing and blow protection fuses, unless you add expensive cell-balancing controllers to each of 6 series.