Hi and welcome to Just Answer!
Payments made to the third party on behalf of a person - are treated as made to that person - and are constructively received by that person.
How to treat these payment - that is a separate issue.
If the corporation buys shares from the shareholder - the shareholder will report the sale transaction - the gain will be (selling price) - (basis).
If the selling price is equal to the basis - the gain will be zero.
Let me know if you need any help with reporting.
You have a bigger issue of the appearance of commingled funds of an owner and a business and the risk that the IRS can determine that the business was used as a personal piggy bank for a shareholder. If the IRS makes such a determination (and I have seen it done), then all the corporation income is taxable and all expenses are treated as personal, and thereby not deductible.
The alternative interpretation is that these payments that are personal in nature are all considered taxable distributions on behalf of the shareholder.
Selling off one, two, twelve shares of stock for this and that is essentially a false use of equity. It's not about how you saying the corporation is redeeming shares one by one, it's the appearance of the whole activity when seen as a whole.
I think you will have MORE problems in arguing that this is redemption of shares and cause the IRS to declare a non-business use of the business entity. In other words, this strategy is incredibly dangerous.
Keep personal expenses OUT of the business for all purposes. Business money and personal money should always been clearly divided and kept separate.