There are some good resources at togetherforlifeonline.com – mainly directed at Catholic couples and/or mixed couples marrying in a Catholic ceremony, but there will be useful information there for you as well.
I realized after rereading my earlier post that a little more context would probably have been helpful to you … first of all, it’s really great that you and your Fiance seem to be in agreement about what you want to do for your wedding, and it’s awesome that you are looking for ways to incorporate his traditions. The reason why it would put him out of good standing as a Catholic to marry in a non-denominational ceremony is that Catholicism regards marriage as a sacrament (this is different from how, say, Lutheranism and other Christian traditions view marriage.)
There are seven sacraments in Catholicism. Three (Baptism, Eucharist/Communion and Confirmation) are “sacraments of initiation” that every Catholic is supposed to receive. Children generally receive them one-at-a-time, adults who join the Church receive them all at once. Reconciliation (aka confession) and Anointing of the Sick/Last Rites are sacraments you receive on an “as-needed” basis. Matrimony is one of the “optional” sacraments, like Holy Orders, that only some people receive depending on their vocation. But, for Catholics, if you are “called to marriage,” it is seen as a vocation and you are called to marry within the Church, even if you are not marrying a fellow Catholic.
So, if your Fiance chooses to marry outside the Church, it is seen as a choice to separate himself from the Sacraments, and it means that he can’t receive Communion (or any of the others, but Communion is generally the only relevant one) until he resolves the issue by having the marriage convalidated (blessed by a priest). If you are open to changing your plans and having a Catholic wedding, you might be able to do so (but your timeline is pretty tight; usually you need a minimum of 6 months lead time to get through marriage prep, etc. Under the circumstances, though, a priest might be able to help you get it done faster.) Alternatively, if you wish to go ahead with your original plans, your best option might be to make arrangements to have the marriage convalidated ASAP after the wedding.
My best recommendation would be to find a priest, someone you feel is a good listener and someone you feel comfortable talking to, and go over things with him. Try to approach him as a potential ally, rather than an obstacle, because having a priest on your side will go a long way toward streamlining the process, whatever avenue you end up choosing. Best of luck to you!