The diodes *have* to be there to protect the regulator against input shorts.
A 4000 series is surely enough, a 4148 is probably enough. The diodes have to last for a countable-few input short circuits, possibly as few as one. The surge current is what matters, and a 4148 will live through a couple of these, probably, depending on how big the output capacitance is that it has to discharge. I can mentally concoct a setup that would kill a 4148, but in pedals a scenario like that would be inconceivably rare.