With a 1 inch solid wood panel be sure to not fit the panel tightly. A one inch solid panel will expand and shrink a lot. Even in a modern air conditioned house in the winter heaters tend to dry the air shrinking the panel. In times you open the windows the panel will swell. Then when you turn on the cooling the panel will shrink again. Typical lumber yard lumber is not really dry so buy your lumber ahead of time and let it acclimate.
Just dont fit your panel tightly because if it expands it could break your door. Prefinish your panel before glue up to avoid unfinished streaks showing when it shrinks up.
Edit:. You will live with your door for a long time. Get input from the chief cook and bottle washer. If mamma aint happy aint no one happy.
I have a set of Frued adjustable cope and stick router bits. You can make extened tenons for heavy doors. They adjust for thick doors even entry doors.