Just like the Avalon, the Klondike will work with how the ASIC was designed to be used. Instead of 10 chips/bank I'll have 8.
Sorry I haven't followed Avalon's design closely. Could you clarify that Avalon would also lose all 10 chips in a bank if any one of them failed or was damaged?
Yes, to the same extent, as I use the chips in exactly the same way. This wouldn't happen if the hash engine was damaged but would if the data path from input to bypass output was broken somehow.
edit: Note that technically it would only lose those after the dead chip in the chain, so some random number from 1 to N.
The chips are supposedly 100% tested at the factory. I think TSMC is trustworthy that way, seeing as how they're a huge tech company supplying most of the worlds other huge tech companies. Presumably a board assembler would also detect this during testing.
OTOH, doing DIY reflow at home is more likely to experience problems as getting the reflow profile perfected to assure consistent results may be more than most can manage.