Mortgage and HELOC at the same time?

[Luisa Trigo]

Hello,
Our back up contract was unexpectedly accepted so the timing on everything shifted before we had everything lined up. Hence, we are about to close on a mortgage for an investment property and we are in the application process for a HELOC with a different lender. Our mortgage bank is now saying that we have to reduce the credit line of the heloc to stay within DTI guidelines. Will the HELOC also ask to reduce because we will have a mortgage by then? Is it best to address this with the heloc lender asap or close on the mortgage and then handle the heloc. What would be general advice when working with two lenders, two products, and the timing of everything? Is it best to be fully transparent or to keep conversations separate with each lender/product/timing?
We are using the heloc to complete the down payment and have rehab money. We are using the mortage to purchase the property.
We are starting out so new to financing sequencing. We're thrilled our back up contract was accepted just caught off guard with the financing timing not in place. Any insights appreciated.