Slavery
The Marquis de Lafayette was a firm supporter of the abolition of slavery.
As earlier as February 1783, prior to the ending of the American Revolutionary War, Lafayette proposed to George Washington a radical idea that he hoped would phase out slavery across the United States and the Caribbean.
On 5 February 1783, Lafayette proposed to Washington:
"Let us unite in purchasing a small estate, where we may try the experiment of to free the negroes, and use them only as tenants. Such an example as yours might render it a general practice; and if we succeed in America, I will cheerfully devote a part of my time to render the method fashionable in the West Indies. If it be a wild scheme, I had rather be mad this way, than to be thought wise in the other task." (Fitzpatrick, 1938)
Washington replied on 5 April 1783:
"The scheme, my dear Marqs. which you propose as a precedent, to encourage the emancipation of the black people of this Country from that state of Bondage in wch. they are held, is a striking evidence of the benevolence of your Heart. I shall be happy to join you in so laudable a work; but will defer going into a detail of the business, 'till I have the pleasure of seeing you." (Fitzpatrick, 1938)
While the idea did not lead to much, Lafayette did trial the idea in 1785 by purchasing a plantation in French Guiana in 1785.
Despite his support for black emancipation, Lafayette was not involved in the French abolition of slavery in February 1794 (Lafayette had defected to the Austrians in August 1792 and was no longer a leading revolutionary).
Religious Minorities
Prior to the Revolution, Lafayette actively supported the rights of Protestants in France, which had been suppressed since Louis XIV revoked the Edict of Nantes in 1685.
On 11 May 1785, Lafayette informed Washington of his decision to help the Protestant minority:
"Protestants in France are under intolerable despotism. Altho' oppen persecution does not now Exist, yet it depends upon the whim of King, Queen, Parliament, or any of the ministers. Marriages are not legal among them. Their wills have no force by law. Their children are to be bastards. Their parsons to be hanged. I have put it into my head to be a leader in that affair, and to have their situation changed." (Stanley, 2018)
Subsequently, Lafayette spent weeks in southern France investigating the plight and desires of French Protestant communities. He also lobbied for their rights during the first Assembly of Notables in 1787 and worked with like-minded ministers to grant Protestants greater freedoms.
In mid-1789, the Marquis de Lafayette wrote multiple drafts for the Declaration of the Rights of Man (Schama, 2004). While the draft Lafayette presented to the National Assembly in July was not adopted, the draft did contain text which explicitly called out the freedom of religion provided it did not disturb the peace.
Sources:
John C. Fitzpatrick, The Writings of George Washington, Washington. DC: United States, 1938.
Jason Lane, General and Madam de Lafayette: Partners in Liberty's Cause in the American and French Revolutions, Lanham: United States, 2003.
Le Marquis de Lafayette. Editors Stanley J. Idzerda & Robert Rhodes Crout, Lafayette in the Age of the American Revolution-Selected Letters and Papers, 1776-1790, London: United Kingdom, 2018.
Geoffrey Adams, The Huguenots and French Opinion, 1685-1787: The Enlightenment Debate on Toleration, Waterloo: Canada, 1991.
Simon Schama, Citizens: A Chronicle of the French Revolution, Great Britain, 2004.