re: Pay $1,000 extra to house or invest?

Do either of you have a 401k or other pre tax retirement plan? If you have $1000 post tax that's like $1250+ before taxes.

I'd take a 25% instant gain on a pre tax retirement plan first.

If your are planning on more kids $1000 doesn't go far.

No way especially with a mother would I rely on a pension requiring 30 years. I'd consider it pure fluff unless she is under 10 years away.

ETA: I'd also make sure you had at least $25k in equity in your house so if you ever need to sell you can walk away without owing anything.