re: More extreme cheapskate measures...

That looks like a pretty good grade mdf, but I would be a little concerned about the strength of the rails to the sides. I might have bit the bullet and splurged for the poplar. I think with wood movement you’re going to have the same effect at the joints with the mdf as you would with the poplar, but I could be wrong. I just hate screwing or nailing into mdf endgrain. If it were me and my drawer fronts were overlay, I would glue and pin some 45 deg.angled blocks onto the top and bottom of the rails just to make me feel better.
It is what it is though, it’s not a deal breaker, and once it’s installed it’s not going anywhere anyway so I wouldn’t worry about it. Just putting in my thoughts.(which don’t always mean much)