At a Yeshiva there is a person who is in the process of becoming a ger, it was asked if they are allowed to give him any of the following kibbudim: Pesichas ha’aron, hagbah, or glilah. While it may not be a “kavod” to the tzibbur to give these kibbudim to a goy however the question is if it’s muter at all in this case with a soon-to-be ger.
Although the Rambam writes that non-Jews are able to perform mitzvos, and to receive reward for them, the Radvaz explains that this does not refer to matters pertaining to kedushah.
Although this does not imply a direct proof for the question, it would not appear be proper to give a non-Jew honors related to the kedushah of a Sefer Torah. Moreover, this will be a zilzul in the honor of the congregation.
I consulted over this question with Rav Asher Weiss, who agreed that a non-Jew should not be given honors such as hagbaha, but was unsure concerning opening the Aron.
Perhaps he could be honored with opening the Aron for Avinu Malkenu and selichos, which will certainly be fine, or even for holding the second Sefer Torah where two are read.