Cyberware and smartlinks can be easily fixed by using DNI and skinlinks rather than leaving the wireless functionality on. Keep your commlink in hidden mode, with a good firewall, and don't use it unless you absolutely have to communicate with other team members. Sensors are harder to deal with. Remember that an ultrasound sensor of your own can be set to passive mode, to detect enemy ultrasound.
Radar can be jammed, although jamming pretty much lets the enemy know that they have incoming hostiles. I think you're overthinking with the muzzle flash - if you are mostly invisible, the brief flare of your gun going off is unlikely to alert anyone. As long as you suppress the sound, you should be okay.
Astrally, there is not much you can do, although manatech such as FAB grenades can help. Try to go through areas that you know are warded or have a background count. Go indoors where astral visibility is limited, and astral beings can't take as much advantage of their three-dimensional movement. Go somewhere underground.
