Is this allowed: can I get an escort to convert to Islam, marry her and pay her, be intimate with her and then divorce her afterwards
This borderline-haram scheme seems to be a way to have sex without sin. The husband would need to be a Muslim in order to marry a Muslim woman. It seems inconsistent for a Muslim man who cares about avoiding sin to implement such a scheme; he's not exactly going to outsmart Allah.
... The (reward of) deeds, depend upon the intentions ...-- Sahih al-Bukhari 6689 (sunnah.com)
Let's break this down:
can I get an escort to convert to Islam,
Yes, that's allowed regardless of a person's profession. In fact, it's encouraged in the Qur'an; Islam Q&A gives a list.
With the usual caveats (one man, one woman; husband is Muslim; woman not yet married; the marriage is legal in the country) then with her permission, yes.
In several schools of thought, you may also need her wali's (guardian's) permission. Not all though; Hanafi being a notable exception.
It's permissible to give one's wife money.
be intimate with her
It's permissible and encouraged to have sex with one's spouse.
then divorce her afterwards
Divorce is permissible (though discouraged) in Islam; see Just reciting "Talak" thrice commits divorce? for the technicalities. Marrying with the intent to divorce is discouraged, and possibly haram: I want to get married with the intention of only having sex?