I think it can be easier introducing a male to two females.

The older females may be a bit dottie...but many males can win them over. We had a male once with Tippy and Sheba. Sheba wouldn't have anything to do with him, but he eventually got her to play footsie with him under the dining room table.

Tippy adored him and they played and wrestled all the time. When Roofie was ripped from us suddenly and went to the Rainbow Bridge, Tippy mourned for over 3 months!

If you were introducing a female to these older females, you'd have some friction I would think. We use FOOD to reduce this and I started a "treat" time for each cat once a day. Each one got her own favorite and it worked out well. Alot of friction is about food competition I believe. When they learn that food will be plentiful some of that reduces. You might see what I call revenge eating... the other two might get fatter. Oreo even did this winter, but now has lost it. Tippy did too when we got Oreo, and she lost her fat too.

Be upbeat and friendly all the time to all 3 to reduce friction. Our cats get defensive if we seem loud or angry...sort of like they have to defend us. By being silly, using baby talk, and friendly to all, they will be more relaxed perhaps.

You might like the male....they tend to be friendlier to women than female felines do, on average. I loved Roofie...he was so special! He even made friends with an aggressive deer upNorth!
This is Rufus with Effie the deer... she used to chase our black cats alot...but she allowed Roofie to come close even when she was eating. (We think she thought he was a squirrel). He had a poofy tail like a squirrel, and was that color too-- at least not black. He was fascinated with the deer and was always out there with them, including the fawns.

Good luck, I think it will go well. You'll have to keep us up to date!