There are four separate instructions:
"Sostenuto" here means "sustained" and refers to the overall sound, not to the pedal used. The piece uses the sustain pedal. The specific timing of the pedal depends on the sound the performer wants to achieve.
The minimum amount of pedal would be to ...
The problem with the zoom with integrated microphones is the microphones' orientation which is spherical (they catch everything in the room).
You might want to use more directionnal microphones such as cardioïds and super cardioïds.
For the pedal's squeaking, you can use some lubricant such as WD40 on the metal/metal and metal/wood parts. Graphite as powder ...
I once played in a brand new recording studio and they had a $5,000 "Ribbon" microphone (?). The tech said he could hear the dampers hitting the strings. He also heard an airplane fly overhead. He tried different placements of the microphone and adjusted some filter settings and even the direction and height of the microphone.
Aside from other pretty much reasonable recomendations to relocate or reorient the microphone, there is one thing you can try for a bumpy pedal:
Insert something soft (rubber, few layers of fabric, etc...) in the opening over the pedal. You may need to band it to the pedal in order to keep it from falling off.
I have tried many different recording approaches with my upright over the past 30 years (and two pianos), both in search of decent tone, and to eliminate extraneous noises— not just from pedals, but also from a pesky bench.
My preferred method is to record from behind, with the microphone [or stereo pair] perpendicular to the soundboard, with the sensing ...
The unavoidable truth is that pianos, particularly older upright pianos, often ARE mechanically noisy. Attempts to record one 'in the room' may be doomed to failure. If you can pull the piano away from the wall try micing the soundboard from behind. Or point the mic down into the opened top of the instrument (and discover the hammer mechanism is noisy too!...
Depending on whether it's creaks or thumps from the pedal itself or from the damper mechanism, you could try alternative mic positions.
From the front, aim higher up the body, or mic it from the rear, or even lift the lid & mic it inside.
One of those might just be enough to reduce it - otherwise you're going to have to learn to release less abruptly, or ...