I see no reason why just anyone would not be sufficient to perform the duty but I'd lean more to having a Christian involved....I personally subscribe to being 'dunked'...
Baptism is not something God does...It is something you do...A testimony to God and the world...
I'd recommend someone with experience or at least practice...You want to make sure you come back up...
I was baptized in a lake with bunches of Christians standing in and out of the water singing hymns and lots of prayer...Potluck dinner/picnic after...A memorable experience...
Dunked, water poured, sprinkled water, all are accepted for baptism.
My wife was baptized in a lake after she came to saving faith in Jesus. Even though we were standing on dry ground there were a lot of wet eyes.
People caught up in the idea that you can mandate God to save someone by baptizing that person as a baby either worship a feeble god subject to man's desires, or are so into institutional loyalty they don't see what the Bible says.
Born Again Christians throughout history put targets on their backs by publicly stating their faith and being baptized. These people are some of the greatest witnesses in our history.