Do the fees/expenses affiliated with a non-deductible IRA add to it's Cost Basis; (form 8606)?

[KrisD]

No. If they are billed and paid separately, they can be deducted as a miscellaneous expense on Schedule A subject to the 2% rule (only amounts over and above 2% of your AGI count). If the fees are taken out of the IRA cash balance, the fees are offset when you begin to make withdrawals. Brokerage commissions are figured into the accounts capital gain or loss. 

https://finance.zacks.com/can-deduct-ira-management-fees-5865.html

[Bsch4477]

Management fees paid through the IRA account cannot be deducted. They simply reduce the value of your IRA.

On the other hand, management fees paid by cash or check and are not deducted from the IRA can be deducted as investment expenses.

To maximize the growth of your retirement account, arrange to pay any management fees with your own funds before the fees are taken from your retirement account.

[dmertz]

Regardless of whether the fees are deducted from your IRA balance or you pay the fees separately, the amount of the fees never adds to your basis in nondeductible traditional IRA contributions.

While paying traditional IRA fees with non-retirement funds will maximize the growth of your IRA, it also reduces your non-retirement savings of money on which you have already paid taxes.  Having fees paid instead from your IRA balance will often maximize your overall savings by using pre-tax money to pay the fees.  Using pre-tax money to pay the fees generally means that some money that would eventually go to taxes is instead paying part of your fees.  Effectively, the federal and (most) state governments are subsidizing your fees when the fees are deducted from your traditional IRA balance.  Having fess deducted from your traditional IRA balance is more beneficial to those with higher marginal tax rates and less beneficial to those with lower marginal tax rates.