Nothing special. With some exceptions you will file this year *exactly* the same as you did last year.
For your daughter, when she files her tax return she *MUST* select the option for "I can be claimed on someone else's return". Since she will be under the age of 19 on Dec 31 of the tax year, and you provide more than half of her support, your daughter does not have any choice in this.
Now your son will be *over* the age of 18 on Dec 31 of the tax year. If he has more than $4,150 of taxable income for 2018, then you can *NOT* claim him as a dependent on your tax return. He is not a full time student as I see it, so his earnings do matter. But do note the IRS clarifies the definition of a full time student as "determined by the school".
So if he is a full time student by the school's definition, then his income amount for the tax year does not matter. So long as your son does *NOT* provide *MORE* than half of *HIS OWN SUPPORT*, you can claim him as a dependent relative. Take special note that the support requirement for a full time student is *NOT* on the parent. There is no requirement for the parent to provide any support to a full time student...not one single penny. If he is classified as a full time student (and I doubt he is) then his earnings don't matter, and the support requirement is on him - not you.
