If this was an Ekta show I would say you are right but as this isn't and our show has never shown anything otp I don't think so.
Their love for Sameer seems genuine... They are snobby big headed especially Mami hence they won't be happy about Samainas rishta but no I don't think they are negative.
All characters are real in our show... They aren't too good to be true or out and out evil though I am finding Taiji quite evil lately but still it's acceptable as there are selfish, jealous and insecure people like her in the real world.
If mama mami were neg we would have known by now
.. Even Ektq doesn't take this long to show characters real face.