Will this neighborhood hold value?

You can't answer this one, and neither can the builder. What you can do is put the five public records that actually bear on it in front of your buyer — and that is a stronger answer than a number would be.

Early phases price low and late phases price high — that spread is the builder's absorption plan, and reading it as appreciation is the first mistake. Ask for the phase-by-phase price history in their last completed community in this market and you'll see what it did there. What's genuinely checkable: the Federal Housing Finance Agency publishes a house price index for this metro, quarterly, going back decades — that is what homes here have actually done, which is history and not a forecast. The Census Bureau publishes residential building permits for this county, which is the supply your buyer competes with when they resell. The interchange has a funding status in the county's capital improvement plan, and "planned" and "funded" are different words. And the school is not yours to grade — pull the district's own report card and the state's, send your buyer the links, and let them draw the conclusion. Rating a neighborhood by its schools is exactly the characterization your broker's fair-housing policy speaks to; read yours, and stay on the side of handing over the source.

The cost of guessing is that you say a number out loud. If you tell your buyer this community will appreciate and it doesn't, that conversation follows you — and you'll have nothing to point at afterwards, because there was never a source. The cost of doing it the other way is about an hour: two public datasets, one call to the planning department, two district links. And it changes what your buyer is actually weighing — not a projection, but how many homes in this community are still unbuilt and how many permits are still being pulled around it, both of which you can look up today.

Pull the FHFA house price index for this metro and show your buyer the last two downturns, not the last two years. Pull the Census Bureau's residential building permits for this county and see whether supply is still climbing. Call the county planning department and ask in these words: "is the interchange funded, is the school funded, what's the appropriation and what's the schedule?" Send the district's and the state's report cards for the assigned school and let your buyer read them. Then ask the builder for the phase-by-phase price history in their last completed community here, and pull those same addresses in your MLS. That last one is the only resale data in this list that is actually yours — use it.