2
Here's my quick answer:

The dynamics would lie in 8th house planets being in square aspect to the 5th or 11th house planets. You are trying to assign the dynamics to the 8th house topics of death, fear, etc. to the 5th and 11th house topics.

Modern astrology has tried to look at the houses as making up a type of developmental whole, and that causes problems. Traditionally the houses seem to have been considered in relation to the all-important ascendant/1st house rather than to each other. They were considered more as separate boxes, but separate boxes that are linked to, and centered upon, the ascendant. When you think about it, why should the 8th house topics of death, fear and other people's money always be in tense aspect to the 5th house topics of children and pleasure and never to 3rd house siblings and and neighbors? There is no natural permanent or consistent connection between 8th house death and 5th house pleasure, or 8th house wills and 11th house friends. The opposing houses are somewhat different in that as a polarity they do directly relate to each other: 1st house self/7th house partner or opponent; 2nd house personal money/8th house money of partner or opponent; etc.

A quick and simple answer ? we'll leave it to others to correct me or add to what I've suggested. :)

4
In modern astrology, houses cannot strictly be square to one another except in a very general sense: only planets or sensitive points in houses would square one another so's you'd notice. You could have a planet in the 5th that would not square a planet in the 8th because the orb is just too wide. However the options for happy aspects between planets in these two houses are limited.

5
I'm afraid you're turning into a house contortionist and doing some serious twisting in order to put these house significations in conflict. :???:
It sprang to mind... when you spend time with friends, you can*`t have sex with partner.
You can if you have friends who like to watch.

When you gamble you spend shared money. . .

I'm not getting this one at all. You have your money, you gamble, you lose it.

. . . and kids disrupt sex.

And so do headaches, barking dogs, house fires, and neighbors unexpectedly popping in for a visit (unless you want the neighbors to watch). :?