Rent increases based on renovations without valid CO

[TenantNet]

As I said, you're low priority as I have 15 people ahead.

These days LL's tend to combine units, not split them. It's called Frankensteining and is one loophole to double rents and deregulate units (there is a bill pending that would stop the deregulation; concern is that Hochul might refuse to sign it). But the actual splitting depends on the underlying facts and if DOB issues a permit. That you don't have a CO now, I don't think that would preclude the actual work being done.

There may be other things that could impact or preclude the work. You get into issues of egress (for each unit), light and air in each room, minimum room sizes and so on. If the work makes changes to the interior hallways, that could create limitations as well (you can't have hallways too narrow). You need to find out what the LL is up to, look at the plans and the DOB application (look for the PW1 document and any zoning documents from the DOB web site).

Location? might be important
Type of Housing?
Age of building?

Are any of the units occupied? LL can't do that to occupied apartments.

There are all sorts of things we can't answer. You can consult with a tenant attorney, an architect. I've been there and know the dilemma.