Big HUGE hugs and hopes for you and your family... being in a dual faith family is hard, but once there are kiddos in the mix it can seem nearly impossible some days. You might want to ask for local advice or see if there are some local "religious/spiritual" education options that might help as a family. For example, dual faith families are not that uncommon in the more liberal Christian and Jewish communities and a priest or rabbi in one of those communities may be able to offer counselling or the name of a counselor who is "good with" dual faith family issues. And I think I know more Unitatiran Universalists who joined their local UU community specifically because mom and dad have different beliefs and they wanted a common ground of acceptance for their children. (UU is, in some ways, a spiritual umbrella religion in that it does not provide a list of "you must believe/you must not believe" or a list of "these are holy books/words/ideas that must be accepted"... individual members might identify specifically as Unitarian, or they may identify as Jewish-Unitarian, Christian-Unitarian, Pagan-Unitarian, Buddhist-Unitarian, Secular Humanist-Unitarian, etc). And the UU community offers a pretty nice religious ed program for kiddos that honors a lot of different religious paths without ever telling the kiddos "this one is right, this one is wrong". There's even an online religious ed program that you might find helpful/adaptable for your own personal use in approaching these issues with your DH and daughter. (Here for the main website, here for the Religious Ed bit).
My own story is that when DH and I met we were both Catholic (I was raised in a very conservative/observant family, he was raised in a much more secular Catholic family). My personal beliefs were changing however, and by the time we were married I no longer considered myself Catholic, though I did identify as "Christian". We got married outside of the Catholic Church, and over the years we both evolved in our beliefs. When dd1 arrived DH was still "mostly Catholic" and I was firmly Pagan. We went along with a lot of Catholic tradition though until dd2 arrived and I realized I just couldn't accept that anymore, and by then DH was more closely aligned with Pagan beliefs anyway. We lost a lot of friends and family members when we decided not to baptise dd2. But DH and still dealt with the difficulties of being a dual faith family. We joined the local UU church so the girls would have a wider and more diverse spritual community, and so they'd get the "there is no one true way, different people believe different things" message from a wider range of adults/peers. Fast forward to today and this is the FIRST time in 18 years that DH and I are on the same page in terms of religion. We're expecting our fourth child and finally can say we're a "single faith family". But we both know that this might change, and we're ok with that.
But the thing is it took a LOT of work, and love, and acceptance, and compromise to get through the dual-faith years. Having a neutral talk with your DH is the most important step right now, so that you can both figure out on your own as well as together what elements you can or can not live with in terms of religious education for your children. What outside influences are important, what personal convictions are the most important, what convictions can you let slide or adapt or compromise on? You'll BOTH have to find ways to compromise and adapt, a one sided agreement /can/ work in some cases but I only know of two families where that sort of "the children have your religion, I'll keep out" has worked out without a lot of eventual resentment. This is where an outside counselor or spiritual guide could be really helpful... religion is such a foundation issue that even trying to discuss it neutrally can be hard, and once emotions and possibly hurt feelings are added to the mix it can be deadly.
In my case, we told the kiddos that different are different... some like chocolate ice cream, some like vanilla. Some people like to hike, some would rather ski, others would prefer to sit in a rocking chair and tell stories. And that these differences are all ok, and wonderful, and what makes the world an interesting place. And we read all sorts of children's stories about different religions or traditions. On our shelves right now are:
All I See is a Part of Me
A World of Faith (Each page describe a specific religion in very "equal" terms, the illustrations are good places to start conversations)
The Story of Hula
To Everything There is a Season (uses the biblical quotation, but each line is illustrated with art from a different world religion)
The Star-Bearer (we edit this as we read it, some of the content is too mature even for our 6yo)
The Desert is My Mother
Sacred Places (poetry, each poem is focused on a different spiritual path and the illustrations are wonderful)
Big Mama Makes the World (a very biblical creation story but with "Big Mama" and her "Baby" doing the work of creation between batches of laundry and making cookies... it's really sweet and a favorite read aloud bedtime story here)
Child's Book of Blessings and Prayers (from all over the world, we use these for meals, bedtime, daily circle time, etc)
One City, Two Brothers
And again, we keep stressing how everyone is different in some ways but the same in others, how important it is to learn from others and teach what we know, and so on... only applying that to religion as it comes up (so we're not singling out religion as being different than other parts of life). And we'd sort of relate religion back to more concrete things in our kiddos lives... I remember once dd1 was asking about why mommy had many gods and dadda had only one (she felt bad for DH actually), and I used the example from Sesame Street where Cookie Monster had to pick between one BIG cookie or many SMALLER cookies... in the end it was all still cookie, and Cookie Monster was happy, but the way the cookie was presented was different. Same thing with Mama and Dada... Mama had many smaller cookies to choose from while Dada perfered one big cookie. (not a perfect example of course, but for the moment it was perfect and really all a 4yo needed to know in the moment)
I wish I could say there was an easy-peasy path through the dual-faith-with-kiddos forest but there really isn't. Just hang in there, be honest with yourself and your partner, and take it one step at a time without jumping to worst case scenarios. People change, and it's silly to think that they don't/won't. Religion is emotional and ties into all sorts of social elements as well so it's a harder change to negotiate, but it CAN be done!