Is it allowed to make a public facebook post that you are looking to get married. Then a woman sends her information in private message. Afterwards you directly ask for the number of her wali/mahram. Is this interaction allowed? Just the basic information so that you can continue with the mahram

Ustadh AbdulAziz al-Haqqan

Announcing that you are looking to marry is fine, and asking only for her wali's number so that you continue with him is what is needed. What is not encouraged is private messaging to get to know her, so keep it to that one step and take it to her wali.