Yes, use your anticipated carryover amounts, particularly if the CPA can provide you with those amounts before you file your 2018 tax return. The fact that the the IRS may still be processing the 2017 amendment will have no effect on the initial IRS processing of your 2018 tax return since the IRS only looks at your 2018 tax return for initial processing. Any correlation of your 2018 tax return with prior year tax returns, if the IRS does any at all, will likely occur no less than a year after filing your 2018 tax return.
