Is this a 'trust fund scam'?

You can't verify this person, because anyone can put anything on the internet and (assuming you are not a government agency) you can have NO IDEA whether it is real / legit or not.

However, you are right to be suspicious and I'm afraid this is a scam. Think about it - if you were elderly and had no family and plenty of wealth, would you find a stranger on the internet to donate it to? Or would you find a charity or organisation you supported, or a long-time family friend?

The "person" (individual scammer, or group of scammers working together) you have been corresponding with has unfortunately tried to take advantage of you. They are currently sussing out how gullible you are and trying to get some identity information out of you along the way. If they get hold of your identification data they will use it to open accounts in your name or for other identity fraud. They will likely also start asking you for money - like "I have this inheritance ready for you and you just have to pay $1000 in lawyer's fees" or whatever. In reality there is no inheritance of course but they will keep fleecing you for more money until you eventually figure out it's a scam.

The best thing you can do is stop responding to them at all, there is no point trying to ask them questions to figure out if it's real or a scam, or to figure out exactly how the scam works. There's not much point reporting them to the legal authorities where you live, either, unfortunately. You could report them to the penpal site you met them on, but if this account gets suspended / blocked they will just set up another one, so it's up to you whether it's worth the time to report it. (The only exception to this is if you have already provided them with your identity information, in which case you should pull a copy of your credit report and put a fraud alert on your record so that no further attempts at fraudulent use of your ID can be made.)

I'm sorry this didn't turn out to be real. You were right to have your guard raised, though.

I can't tell you how many times I've said this to people on similar questions - If you have to ask the question "Is this a scam?" then the answer is almost always YES!!!

Always ask yourself why someone who doesn't know that YOU are any more real than you know about THEM would suddenly want to be so amazingly generous for no particular reason.

If they want to be so kind to you, why do they need all of this info? Why can't they simply mail you a CHECK?

Any time someone you don't know from the man in the moon wants you to "prove your identity" so that they can send you a windfall, RUN!!!!!

The fact you turned up so many obvious red flags researching this before posting your question tells me a couple things:

1. You're not dumb.
2. You noticed the I.D. seems bogus, and if YOU can tell that, you'd better believe the authorities will too.
3. You can't verify a domain that is "under construction". DANGER, WILL ROBINSON!!!
4. If you go through with this, you run the very real risk of being caught up in a money-laundering scheme or something else illegal (and perhaps WORSE than money-laundering).
5. You could end up on watchlists because of the people you're dealing with if it turns out they're known to be scamming people. There's no reason the authorities wouldn't consider you part of the scheme, right?
6. Does it really sound kosher to you that some little old lady would so willingly turn over money to a complete stranger?
7. Who is this person she put in contact with you, and what's their part in all of this? It isn't as though she said an attorney or other official representative of her estate would be contacting you, so who is this dude?
8. If the email from this guy went to your spam folder then it means either the domain he's sending it from, or more likely his specific account, have been flagged as sending out spam emails to others. DANGER!
9. What's to stop these people, once the money is sent (or as part of the deal to send it at all) is that you have to send some of it back or on to someone else? This is a variation of an age-old scheme.

You showed enough sense to ask people for advice. Now show enough sense to follow it. This doesn't have red flags, it has flashing lights, blaring sirens, and all manner of danger signals going off. Stay out of it.