All it would take is her husband to be Novus Ordo, and voila -- funeral will be booked at the Novus Ordo.
I think the "attorney given instructions to have a Tridentine Mass" etc. only applies when someone is single/widowed -- or if your spouse is OK with following your "Traddy thing" after your death. Remember, the non-Trad spouse never darkened the door of a Trad chapel EVEN ONCE while the spouse was alive. Unless the spouses worked something out beforehand, the "Novus Ordo" spouse is going to go where he/she is most comfortable.
Let's put it this way -- it's like inheritance. When one of your parents dies, you don't "inherit" anything, strictly speaking. It all belongs to the surviving spouse. Now your mother/father might GIVE you some mementos, personal effects, etc. from your deceased parent -- but it's more of a gift, not an inheritance strictly speaking. When one of the parents are still alive, their "estate" stays with that parent. Maybe it's analogous to that.
We recently went to a funeral of a very devout Trad man -- he was one of those "Trad single" men who "seems" single at Mass, but was actually married. His Mass and burial were Traditional -- but then again, he was the man of the house. He might have arranged the funeral himself, or had someone do it for him. If the wife were the Trad one, it might be more difficult...
I think it would depend on the Novus Ordo presbyter ... where perhaps some would give her the funeral even if she wasn't a member of the parish, whereas others would not. Perhaps she was registered there somehow, and then never withdrew the registration. Some presbysters would do a funeral for a departed Jew, but would exclude a Traditional Catholic. It's like where Novus Ordo "bishops" would refuse to give or sell churches to Traditional Catholics, but would sell them to any Prot denomination. I know of a couple cases where SSPX acquired churches being shut down by the Bogus Ordites only by hiring a Baptist minister as a front-man for the purchase, who then immediately executed a Quit Claim deed to SSPX, and in one case obtained a beautiful building that would have cost millions to build for $50,000 ... via the Baptist, after they had turned down offers for much more from SSPX.
As for giving an attorney instruction, you can certainly do that, even if you're married ... where you put that in your will and appoint the attorney as executor of your will, if you think your spouse might drag you into a Novus Ordo church. Yes, the surviving spouse by default holds the decedent's "estate", but that's only the default, and it can be overridden by leaving express instructions to the contrary. Now, "marital assets" in most states' laws are all owned jointly by the couple, and so there's no transfer of any kind, nor can one of the couple leave "my property" to their children rather than to the spouse, since it's all joint marital property (again, that's in most states). Exceptions to joint marital property would be things like anything you inherit from your side of the family. Now, that's only in secular law, whereas in Catholic moral principles, that's not true. Even if the wife inherits money from her family, legally it's hers and hers alone, but morally it belongs to the household and the husband is in charge of administering those assets.
If I were in a situation where my wife might bury me in a Bogus Ordo church, I would make my intentions to the contrary widely known to anybody who would listen and leave instructions in a will, and appoint an attorney I could trust as the executor of my will. At that point, the wife would have to deliberately refuse your wishes and move very quickly before anyone found out that you even had a will. But then, in my case at least, I would tell my siblings, who are all Traditional Catholics to immediately contact the executor upon my demise. They would certainly at least hear about my death, even if the wife were hastening to get my butt cremated and have the Novus Ordo scatter my ashes to the wind.