Hi all - I've got a question about wording on announcements/invitations. We have sort of complicated families, and I can't find anything that fits this very well! Any thoughts you have are greatly appreciated

My mom will be paying for the majority of the wedding, with my fiancé's mom chipping in the traditional amounts (flowers, rehearsal dinner, etc.). It's very important to my mom to have her name on the invitation - as in, "[Mom] requests the honor of your presence..." She is recently widowed, though, as my dad passed away not too long ago, so we're unsure whether to put his name on there as well.
My fiancé's parents are divorced, and both have re-married. His mother has a same-sex partner, and his father has another wife. His mom's partner has been a HUGE part of his life, so we can't just leave her off and put his parents' names on there alone. I suspect it should look like any other divorced/re-married family, but my conundrum is that I can't find much in the way of etiquette/suggestions that deal with the groom's parents being re-married - only the bride's.
Thoughts on either/both of these situations? Thanks

Re: How to handle deceased parents/re-married parents on invitations
This may not be what you want to hear, but...
Paying doesn't equal hosting for the purpose of weddings-but who the "point persons" - that is, who issues the invitations, receives the responses, greets the guests, and ensures that their needs are taken care of does.
Deceased parents are not named on invitations. That's because they can't host and aren't the honorees. That said, you can have a page in your program, if you are doing one, in which you can give your father a tribute.
Also, the purpose of the invitation isn't to map out the family trees or who's paying for what (which isn't any of the guests' business anyway). It's to convey logistical information about the underlying event to your guests-the what, when, and where.
With the remarriage issue as well, instead of naming all the parents, I'd use "Together with their families, Bride and Groom etc.
Bride Fullname
and
Groom Fullname
Together with their families
Bridesmom Lastname
Groomsmom Lastname and Momspartner Lastname
Dadswife and Groomsdad Lastname
request the pleasure if your company blah blah...