F1 cars are required to have an automatic 5 litre fire extinguishing system that aims at the cockpit. Olivier Panis' went off accidentally at the 2004 British Grand Prix. If it required any buttons to operate, it would be against the rules as it is supposed to still work even if the driver is overcome by fumes or otherwise incapacitated. I am not entirely clear on what conditions the automated system is obliged to run. The extinguisher has to be, at least in principle, driver-accessible in case a situation arises where this is the better option. (Not sure how accessible any of the actual solutions are - I think they'd all need to be fished out from the base/side of the monocoque well, rather than be in a logical location).
The headrest would be a good solution for the anchor point were it not made from collapsible foam.