hello i'm playing carthage in EB and have been told that egypt will be a major problem later in the game if the sleukids do not last (this makes sense as they gave me a helluva time as the numidians on vanilla rtw). basically i need ways to keep them in check without causing open hostilities and i was wondering a couple things:

can giving cash sums to the seleukids prevent their empire from crumbling and how much loot should i offer? for that matter can you stop the defeat of any given faction if you give it enough cash gifts? (i've been trying to keep the epirotes strong for the eventual battle with rome)

how effective is it to get the enemy to attack someone for you? right now i have been getting the arabs from saudi arabia and the seleukids to attack the ptolemaics , for about 5 grand each time, one after the other in an attempt to keep them in check, but due to the darkness on the map i never really know what comes of these attacks.

finally would it be effective to infiltrate the capital or some other huge city at the mouth of the nile with spies so i know the gates will be open when i lay siege, sack the city and utterly destroy it with a temporary army, and then leave by boat and sue for peace after the next turn? seems like i read somewhere that the PC has no build times and cash so i wasn't sure if this would appreciably set them back.