Forgive me but your original question
"Does god always keep creating new souls? ie souls with a zero balance? If souls merge back into vahiguru, then will there not be less species, unless new souls are created?"seemed like you were implying that the soul no longer exist after Mukhti. The Gurmukh specie never dies and stays forever.
In Zindigi NamaBhai Sahib talks about the Khalsa ( Gurmukhs).
Metaphorically speaking BHai Sahib states God created 72 groups and out of all these groups the Najis are the most elevated. Naji is an arabic word for survivor in which BHai Sahib is referring to those Immortal Gurmukhs who survive they never die . They are true residents of Anandpur Sahib. They come whenever they want in this world. When the room is full of Anand most likely these undying Gurmukhs around.
Here are some of the things Bhai Sahib says about these Undying Singhs
Ehna Noon Rab dee Yaad bina (n) koee cheej changee nahee lagdee
Bandagee ty paat bina Uhna dee Hor Koee Maryada Nehee (N)
They are completely carefree without any desire for worldly things. Only remembrance of WaaheGuru Ji is good to them.
They have no other way of life but to besides Bhagti
Uhna Dy Shaba(n) Vicho Khand tey Misheree j(h)rdee heh
Uhna Dy Har Val To(n) Amrit Di Burka Hundee Heh
Their life giving words contain sweet holy sugar ( mishree)
Inside their hair rains ambrosial nectar.
and my most favorite description about Sant Siphais
Uh Hr Sukkee Lakharh Nu Haree Bharee Banha Dindey Hun
Ub Bu Nu Vee Kastooree Bahna Dindey Hun
They bring fresh green to dried wood ( soul)
They bring divine fragance to bad odored soul.
Waheguruuuuuuuuuuuuuuuuuuuuuu!
In this beautiful divine poetry BHai Sahib mentions such blissful Souls give company to those whom practice humility. May GUru ji destroy our Ego and give our Atma the company of elevated divine souls.