I think my following sentences are okay. Do you agree with me?
Apparently there are a lot of people who have never once been abroad.
Simple present + present perfect tense
Apparently there were many people who had never once been abroad.
Simple past + present perfect tense

But what if I change the tense in the following way.

Apparently there have been many people who ????? never ???? abroad.
Apparently there had been many people who ??? never ???? abroad.
Please complete my sentences according to the given pattern in the sentences above.