The discounts and extended payment option choices with the Lowe's card are given at the register, not as statement credits; it is extremely unlikely that you would receive discounts on those paying with a Lowe's card. If you are planning to purchase a home in the next year (or even 2 years), it is generally advisable to not apply for any credit products until you have the keys in your hand. While you may save some interest on gift cards now, you could end up paying tens of thousands of dollars in additional interest depending on how your credit is at the time of financing your mortgage.
If you are concerned about a strange starting line on the card later on, if it happens just call the overseas Credit Solutions number and ask for a real credit line. As long as your credit supports it, it's quite easy to get a $17,000 or higher starting line.
Just added a $500 gift card to the cart and went to the payment screen. It does look gift cards would be eligible for the promotional APR, but not the 5% savings (if this were another item, I would get 10% off due to my veteran discount (not stackable with the 5%) and an option to use a 0% promotional offer).