More can always be said, but this question has come up before on AH, and you might like to review some of those earlier discussions while you wait for fresh responses to your query:

• US slavery was constructed along racial lines. While contemporary attitudes to skin pigmentation and "race" were not identical to those common today, the simplest answer to your question is that enslavement was limited to black people. With u/sowser
• Free black people could enslave other black people in the U.S., explains u/freedmenspatrol. But this was rare.
• Believe it or not, internet memes aren't always reliable history. The Irish were never enslaved, either in the US or in other British colonies. Our FAQ includes several important resources that cover this controversy, led by u/Irishfafnir and sowser

In a way, yes- for a given value of 'white.'

Race was constructed much differently in the 18th-19th centuries. Many slave states had a 'one drop' rule- if you have even one drop of African blood, you were considered black. Another common rule was that if you were born to a slave, you yourself were a slave- even if you were born to a light skinned slave woman and a white male.

Because of the preponderance of sexual abuse of slaves, it was common to have mixed race slaves who were of lighter complexion.

Indeed, there was an entire industry built around the trade of 'Fancy Maids'- mixed race, fair skinned female slaves meant for concubines to white masters.

(here's a good masters thesis that goes into that sordid field: https://scholarcommons.sc.edu/cgi/viewcontent.cgi?article=4647&context=etd )

For example, Sally Hemings, slave of Thomas Jefferson and mother of several of his children, was mixed race. She was described as follows:

“Sally was mighty near white...Sally was very handsome, long straight hair down her back.”
Formerly enslaved blacksmith Isaac (Granger) Jefferson (1847)

“Light colored and decidedly good looking.”
Jefferson’s grandson Thomas Jefferson Randolph (ca. 1851)

In the Census she was recorded as being mullato; in the next, as white.

(https://www.monticello.org/sallyhemings/)

So, all of this is to establish that it was common for people most Americans today would think of as white to be slaves- the 'one drop rule' and similar laws prevented them from claiming whiteness in the America of the 1700-1800s.

Knowing this, it is possible that a free black man could have purchased a 'white', mixed race slave. This may likely have caused controversy of course, but I have no specific information or cases I am aware of offhand.