is it the whole duration of a muqabala that a man (serious about marrying the woman) can look at her without hijab+niqab,gloves etc? or is it a quick glance at another time than muqabala and she's covered during it?

Ustadh AbdulAziz al-Haqqan

Yes she appears before him and speaks to him. She can even show her hair as well as is the fatwa of Imam Ibn Baz.