are the rights of resident aliens protected under the bill of rights?
The US bill of rights applies to everyone in the US, a citizen or not, even those here illegally.
Aliens don’t have all the rights of citizens. They can’t vote, can’t serve on juries, and can’t hold elective political office and some other goverment positions. A natural-born U.S. citizen can’t be deported, a naturalized citizen can be deported only if his citizenship is revoked (which is rare). Aliens can be deported, or excluded from entering the country, quite easily. There are different classes of aliens with different rights: Permanent resident aliens have most of the rights of citizens, parolees and illegal aliens have fewer rights.
Correct. But the OP was asking about the bill of rights, which is used to refer to the first ten amendments. Those talk of “people”, not “citizen”. I agree that there are parts of the constitution that give rights to “citizens”. Those rights would not apply to non-citizens. Laws can also distinguish between people and citizens, subject to constitutional restrictions.