Increment end date +1 if a range has a holiday

Question

Currently making a document where there will be four rows of dates. This is for a cycle for a product I'll be managing through Excel.

The dates will always be the same distance apart and I have the formulas set. Is it possible to add +1 day to my formula if the range has a holiday?

There is a start date, testing date, regression date, and completion date.

The start date will be set somewhere in the doc, and then I call the

start date as
=TEXT(J2,"mmm dd")

Testing dates as
=TEXT(C2+1,"mmm dd")&" - "&TEXT(C2+15,"mmm dd")

Regression will be
=TEXT(C2+16,"mmm dd")&" - "&TEXT(C2+21,"mmm dd")

And completion date is
=C3

The only other change from here, is the next row, start date

has
=TEXT(C2+28,"mmm dd")

Table Example

Is there somewhere I can setup a table, or any option that is possible through general formulas or VBA, that if the date or date range has a formula in it (example Jan 1st New Year's, or Dec 24th Xmas), it will add 1 to the formulas.
Either change the C2+28 to +29, or ((C2+28)+1).
There will be 12 holidays every year to manually enter and was hoping it would be possible to automate.

This will be used many times so it would be nice to have it as a set it and forget it, and to possibly generate the next 10+ years without having to change anything.

Example:
Start: Dec 28th
Testing: Dec 29th - Jan 12
Regression: Jan 13 - Jan 18
Completion: Jan 25th

So because New Year's is on Jan 1st, it would then change testing to
Testing: Dec 29 - Jan 19.

Answer 1

WORKDAY will probably work for you, as long as your start and end dates are on weekdays. It excludes all weekends, and you can specify a list of holidays to exclude.

Instead of =A1+28, use =WORKDAY(A1,20,$D$1:$D$9). Note that instead of 28 calendar days, there are 20 working days.

The 3rd argument should point to a list of all your holidays that you want to skip.