Phenol has pKa of ~ 10.0 while p–bromophenol has pKa of less than 9.35 which indicates an increased acidity compared to phenol. When a halogen is attached to a benzene ring, it is difficult to undergo nucleophilic substitution & other substitutions.

Aminoguanidine bicarbonate has the structure HN=C(NH2)(NHNH2).H2CO3 so the chemist will expect an acid-base reaction of p–bromophenol with the –NH2 groups but the presence of the carbonate part will not help this reaction because it is weakly acidic.

I do not think that it is possible to obtain para-aminoguanidylphenol since (Br) cannot be replaced & if there is an interaction, then it will be a weak one on the 2 amino sites.

Aromatic guanidines are usually synthesise by reacting aniline with cyanamide or thioureas. See this link for some references:

https://www.organic-chemistry.org/synthesis/C1N/guanidines.shtm

Starting with 4-bromophenol will most likely mean converting to an appropriate amine. 4-aminophenol may possibly be used with protection of the phenol.

Thank you for your answers, Nizar and Eugene!