Long+Pics (little history)+question re: cat companion & males/females (please advise)

Welcome back!

You are thinking on them like humans? The male part should be somewhat older and so?
I dont think that matters with cats.
I agree with you many people feels male cats often tend to be more lovable and cosy, girls more indenpendent. And neutered males often gets good friends with spayed females. Even in cases where this female is supposed to hate other cats.
But age doesnt really mean much.
The real question is not 10+, but kitten or grown up.
Kittens and youngsters are a bit complicated, they may be too much for an older cat. (although I know some older cats in fact gets revived by a kitten!).
So my recommendation would be a 2+ male cat. With the additional plus, when it is time for your girls to go on in perhaps 5 year, you will have this male left to bevare the continuum, and introduce a new younger cat.

How to safeguard the newcomer will be friend with the residents?
You dont have any 100% guarantiees, as cats are individuals.
You can increase the chances by choosing one you KNOW is a sociale cat. Say, if you get your cats from a good shelter, they should know who are good candidates. You can also use a Feliway diffuser during the introduction period.
Try to get a agreement for a try out period. If it doesnt work out - the cat can go back...
You do of course make some sort of introduction, (you know surely how to do it, you had many cats). Be also prepared for a quarantine/vet check up - you dont want to risk your residents.

You hope of course the new cat likes to sleep in the bed with you. (I know, it is very nice, mine sleeps sometimes; one between the knees, the other on right hip, the first helps my rheumatic pains, the other gives a wonderful relaxation. But it is not always they want to do it...).
But again, you dont have any quarantee for this. Although the chance with a male is bigger than with a female. And WHERE in the bed it will sleep - you dont know at all. You must look and see.

Good luck!

I can say working with thousands of domestic cats in shelters across the USA, doing my own fostering/re-homing over the years, and keeping personal cats I will say all cats are individuals.

However, male cats seem to be more "steady" in temperament. What I mean by that is, if a male cat is sweet he tends to be sweet most of the time. But if a male cat is not sweet he not sweet most of the time.

While female cats seem to "run hot and cold". What I mean by that is most female cats can be sweet and loving one minute/day and then standoffish the next.

Note, these are just my personal experience.

At my house, the females run the household. Which is good, someone has to.
They seem to be the best hunter too. My males seem to be more relaxed, care free.