Happy to answer!
Which wonders did you manage to get?
In terms of unique wonders, just Stonehenge (a must, see below), Terracotta Army (AI doesn't show much interest in building this), Notre Dame (another must), Taj Mahal, Hagia Sophia and Big Ben. My Egyptian wonder building edge really only mattered to get Stonehenge first, which on Deity must happen or you will almost certainly lose.
At the end, other civs were building wonders way before I could. The Chinese had 10 wonders, all endgame ones (they had one amazing city).
Were you able to found a religion?
Yes, and I consider this essential to winning past Emperor level. I took all the building upgrades (mosques, cathedrals, etc.) I could, and the "30% combat bonus in your own territory" one, which is also essential.
How many techs did you steal?
5 in total. It takes a LONG time to steal a single tech on Deity and spies dies fast.
How many friends were you able to maintain?
Haha

... zero. I was barely able to keep neighbors from attacking me, and at one point was at war with 14 nations at once. No allied city states either (they either get blown out early or making friends with them is too costly, it also leads to AI attacks).
How did you defuse early wars with so many AIs breathing down your neck?
I cycled troops in and out of forward spots and had to let the AI come within city range a lot. I did lose troops, and sometimes thought the wars would be the end of me.
One very lengthy war with the Ottomans to my south was a turning point though. I beat back their initial assault and established good forward defensive positions, leading to something of a stalemate. Eventually they (and the Russians to my east) offered standard 10 turn peace treaties. I thought about it and
turned them down, which was counterintuitive, but I was taking a gamble that they would become war fatigued and offer me stuff later if they continued not to win the war.
Sure enough the Russians offered a huge deal (oil furs, iron, gems, 1,500 gold) and eventually the Ottomans offered the best deal I have ever seen (oil, copper, and a staggering 24,000 gold, when I had about 800 in the bank).
That deal changed everything, as I was able to use all that oil to buy a killer old-war Bomber fleet (15 planes) and take over the Russians later. Immediately (after riots subsided) I was able to rehabilitate their capital city using gold. Then I took the two big Ottoman cities with the same plan, going from 2 great cities to 5 in two wars.
And I was STILL waaaay behind Greece (and behind two other nations). The nukes eventually solved that with Greece, though I had to start another war just to get my cruisers into position to send the nukes (which was awesome)!