For the investment sale entries, I would suggest you enter the full sale amount and then change the cost basis to reflect your share of the profits on the sale. Otherwise, your sale amount will be less than what the IRS has in their records, so they may adjust your tax return later on and send you an invoice for the difference.
On your spouse's return, she can just report her share of sales and cost basis, as the IRS won't have a record of her sales.
When you enter your sale, you should enter the cost basis reported on the form 1099-B, then use the The cost basis is incorrect or missing on my 1099-B option on that screen to adjust the cost basis.
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