So sorry to hear that you lost your mama guinea.

It's a lot of hands-on raising the keets, but it's worth it in the end. When raising them by hand, I keep my keets under heat for 6 weeks and since it's late in the year, adding a heat source in the coop as mentioned above would be a good idea.
Don't be surprised if the male is aggressive toward them. Females can be as well. I've had some males that almost take on the role of mama and others go into "keep away the intruders" mode.
They can get pretty aggressive and sometimes it takes several rounds of introductions and a lot of time before they are accepted, depending on the personality of the male. If you have the means to provide hiding places in the coop, that will help. I use hay bales crisscrossed like Lincoln Logs to make little caves. The females like it for nesting and the keets like it for quick getaway spots.
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Good luck!