This was a big disruption for them and in the grand scheme of things is likely not a big deal for you to cover the meal cost. 

Once the buyer and seller agree on this scheme it's no longer an arms-length sale.

I agree 100% - part of the problem is a lot of RE investing these days is marketed as a get rich quick scheme where you'll be able to buy a few rent houses, make monthly passive income, retire and travel the world.

It's like the crack of the financial world, nothing good can come from such a scheme.

Also, ask them what the most popular colors and color schemes are, since they deal with painters and homeowner directly, they can be treasures of information of what accent colors are being used and where, etc.* Call local property mgr's and/or ask for referrals from your relator friends/associates, and ask them for referrals - sometimes they will be nice enough to offer helpful advice, especially, if you tell them you will consider using them when you turn the house into a rental in a yearAs a 27yr appraiser and Realtor/Broker, the paint job has minimal affect on the value, unless it is so bad that I have to mark it down in quality and/or condition.

It’s not a get rich quick scheme.

Hope things improve moving forward for you and in the grand scheme of things, $2600 loss I would just chalk up to a lessons learned and one you can continue to teach others about in the future.

In the grand scheme of things, yes, you should eventually replace the windows so 1) They operate properly. 2) It doesn't turn away potential tenants or cause maintenance hassles when a new one moves in.3) Tenants have proper egress in case of an emergency (like fire).Now, windows are expensive, so you'll have to decide how much you're willing to spend, based on how much income the property is bringing in.

They will affect what you can and can't do and will affect the home you build (ie exterior finish, landscaping, colour, etc).

It's a get-rich-quick scheme and you are most likely wasting your time.