When my FIL died last year, he had expressed a wish to not have any kind of funeral, and he hoped to have his ashes scattered at sea.
MIL wanted a funeral. Much of the family was leaning toward not having one, my attitude was “they’re for the living, do what MIL wants”. Ultimately, she decided not to push for one - which worked out well in many ways as it would have been tricky to arrange travel etc. We wound up having a family meal a couple months later, once she’d moved to her assisted living place up in NJ.
The ashes: turns out there are boats that actually will take you out past whatever the mandatory distance from shore is where it’s legal to scatter ashes. They’ll either do it for you, or you can go along and do the scattering.
I think it’s disrespectful to the decedent to blatantly ignore wishes like “no religious service” or whatever. Of course, some folks DESERVE that disrespect… But all in all, if honoring last wishes, for a beloved family member, can be accomplished without an undue burden, it may well bring some joy to the family, remembering their loved one at the time of the scattering or whatever.
As a semi-humorous side note to ash-scattering: My mother had spent many happy hours at a country club the family had been members of for generations. She loved to play golf, before her health became an issue. She had once said she hoped that some of her ashes might be scattered on the golf course there.
In Catholicism, scattering ashes is generally discouraged / forbidden. I asked the parish priest, when he came to visit her in the hospital, if her wish was acceptable. He basically said “Hey, what I don’t know won’t hurt me!” (this was the priest who looked like a biker - first “cool” clergyman I’d ever met).
I mentioned the wish to the funeral director. As Mom’s urn was brought to the church, he surreptitiously slipped me a small bottle (a pill bottle, actually). So Mom spent her funeral in the urn, AND in my purse.
My brother took care of the scattering, a few weeks later.