Hope you don't mind me responding as I haven't been through what you are going through but I have been thinking about you all day! So I hope what I am going to suggest isn't inappropriate but I thought I would just put it out there as I do know what it feels like when you lose someone and you want them included in big events.

I was wondering whether rather than having a baby shower with all your female relatives (seeing you are not that keen on them) if you made it a couples event so your DH could be there and have a celebration of Cookie in that way with people you enjoy hanging out with. Then if things do get awkward with relatives saying inappropriate/stupid things at least you have each others support to get through it. After the year you have had you both deserve to be celebrated.

Then on the invitation you could write something like "We invite you to celebrate us becoming a family of 4". And in that way Ianto is included in the invite.

Again hope this is ok.