hoo lots of questions! Welcome to Songstuff.
You've come to the right place
ok... your pedal... pedals are at their most simple, on off switches. They are either down-on up-off OR down-off up-on. Many pedals have an extra switch that allows you to select the behaviour.
In the dark old early midi days many pedals didn't have a switch. they were hard wired in one config or the other. As a result, as midi keyboards became more sophisticated they added an option within the settings for the keyboard that allowed you to select the behaviour (polarity) of the pedal, so that it could work with either config.
most keyboards have a global settings section and the pedal behaviour is one of those settinngs. I am using my phone otherwise i would have checked your manual for you. If you cant find let me know.
The point is... if your keyboard has that setting then you are not limited in terms of what sustain pedal or foot pedal you buy. Yet again i am happy to check and offer a recommendation.
Microphone wise... you are in part going to be limited by how you get your mic signal into your computer. If your interface has +48 volt power button (phantom power) on your input channel then there are no real limits. That said getting hold of a powered interface is not difficult or necessarily expensive.. just worth noting that it may be an additional cost.
I love Rode microphones for their performance and value for money. At home I use a Rode NT2. great mic. Yet again when i get near my pute I can drop you a few links.