question for you - it sounds like there is no home on the property and you are getting a "land only" loan in option #2, is that correct?

#1 is out because no lender I know will finance a construction if they don't know what they are constructing. I am surprised the seller will not hang around for 3 months. Land is not the hottest asset right now, unless yours is highly desirable.
In addition to the multiple closings with option #2, subdividing one parcel into three will require more expense then you may think. Call an attorney and/or surveyor to get quotes.
I would also call one or two more lenders to see what they can offer, but I think your options are the ones you described.

There is a house, but we won't live in it. We actually have someone on hand who would buy the lot that the house would be on, while we'd take one of the empty lots to build on next spring.

The land is in a pretty desirable location. Only reason it hasn't sold yet is the seller won't do the division so it's priced out of most individual's budget (and willingness to survey, divide, and so on). If seller would divide it herself, the lots would probably already have been sold.

Price is also IMO high for a developer to come in and make a good profit, though that is what will probably happen closer to spring, when the building season will start up again.

Seller is an elderly woman who has never done a real estate transaction. Apparently she grew up and lived her whole life in the house. She seems, to put it mildly, to have some odd ideas/beliefs.

Since I don't really have the heart left to call any more lenders, I guess I need to grieve and move on. (sigh)

If it is such a great parcel, why give up so easily? It takes about a 10 minute call or visit to a lender to have them explain their options to you. Pretty simple.
Also, you'd be surprise at what buyers and sellers say they will or will not do, until they are asked formally with an offer.

We've talked to more than one financing agent (all highly recommended) who have contacted multiple lenders on our behalf. My "peripheral" info seeking is that these scenarios are typical and that finding something to accommodate the seller's and our criteria and limitations, is just not something we are likely to find in today's financial climate.

Have also spent 6 weeks making formal offers/counteroffers with this seller. (No, I wouldn't be surprised. In the several real estate transactions I've been involved in or heard about I've been amused, amazed, and disappointed, but not surprised.)

Why not get the party that wants the lot the existing house is on to do the deal? Then buy the lot you want from them.

The seller won't do it (per the OP's post above).

Why not get detailed plans of a house drawn up, knowing that you need them anyhow? You could buy them online in 15 minutes. Or hire someone to draw up some plans... maybe take a month. There is a good chance the lot will still be on the market then.
You really should not look for a lot if you don't know what footprint your future home will be in most cases anyhow.

The other party doesn't have the money to do the larger deal, just buy one of the lots. The house is rather old and many would just tear it down around here, so it doesn't make that lot worth a lot more.

Lot sizes and siting are too variable in the cities we're looking in to pick a pre-designed house. Also, we may end up finding something we can remodel and wouldn't need plans then.

Since we're probably going to use an architect to get something closer to our preferences and lifestyle than the vast majority of ready-made designs out there, we're not interested in spending money on that until we have a property secured.

Really, the particular downsides to this deal can't be changed and do outweigh the desirability. It's just we've been looking a long time and this opp. would've been so good if it could have worked out.

So why can't you do option#2? Yes, it's 3 closings. But lots of people get a land loan. Then a construction loan. Then convert it all to a mortgage.

Sometimes credit unions are more flexible with loans. Another thing, check with your local building dept about splitting the property. Some have real strict rules/codes like Los Angeles County, others are easier to work with. Are you working with your own RE agent? Does she/he understand what is being offered? Good luck

The lot division aspect is not a concern; we have done our due diligence and satisfied on that point.

Drawbacks to option #2 (repeated from above):
-- Higher total cost due to basically 3 "closings". [simply too much money overall]
-- Lender requires an approval process of up to 6 months to sell off other 2 lots. [not willing to be subject to their approval, nor the up to 6 months timeframe]

We have worked with our RE before--she is absolutely excellent. You don't know me and how particular I am, so you can take my word or doubt me--makes no difference because this aspect also is as close to 100% as life gets (meaning there's nothing more we need to, nor can, do to improve).