1. Yes it is logical to assume that you WILL fail at other scum attempts if you cannot succeed with a scout. All scum options use the same checks as far as determining success or failure. You need to have around at least 95% of their total scum strength in order to be 'seen' doing the scum options, and need over 135% in order to do them 'unseen'. Those percentages vary depending on race, but those are the base numbers.
2. 1000 turns is the New Player Protection (NPP) period in Massacre:Conquest2. Because of how the game works, the vast majority of kingdoms in conquest are dead or in NPP. The Massacre format gives you all the turns in one go, and the general method of play is to kill progressively larger NPC kingdoms and work your way up to as big a kingdom as you can before you run out of turns. For the most part, the only players kingdoms that you will see are those who are online and playing at the same time as you (which can be fun), or the kingdom who's king-of-the-hill. In other game formats, NPP only lasts 150 turns, and so you'd be less likely to be surrounded by a lot of kingdoms in NPP. You'd only be told the turns of the enemy kingdom if they were in NPP or you succeeded in scouting them.
3. In order to successful spy on a kingdom you need to do one of two things. Either, get more scum by means of offering or warring for land. Or attack the kingdom using Guerilla Raid. GR uses the T1, T2 and scum troops (in your case Mullo, Lamia and Aswang). The combination of a full troop cap of Lamia (the best strength option for Vampire GR) and the Summon troops spell, ought to gradually take down an opponents scum. Even if you fail over and over, you'll still kill 'some' of them. It might cost you a fair bit of gold though.
4. I don't really understand what you're describing. Walk me through what your doing, what happens, and what you think should happen, step by step.
On a related note. I decided to have a look through the Conquest news logs. It looks like you attempted to scout Nymphsong's king, failed, and then Nymphsong promptly killed you. Death happens a lot on Massacre as it's the only way to get new turns (for the killer or the player killed).
The first bit of advice is that it is completely impossible for a kingdom with 638,999 networth to take on a kingdom with 117,893,803 networth. I'm sure Nymph won't mind me giving you a little intel on the kingdom you were aiming for, but you were attempting to defeat 1,400,000 elite scum with just 3,099 elite scum. To give more context to what you were attempting, his kingdom has 2,621,978 acres of which 863,322 are built and you just had 15,824 acres with 9,310 built.
You need to work you way up to it
If no players are out of NPP and in range, you should start by trying to kill the smallest NPC that you can attack. For you, that NPC has a little over 70,000 acres and about 50,000 scum. You need to get a little bigger out of the starting block to take them on.
I'd probably use the Load/Save screen to initially start using someone else's saved build. The Vampire build entitled "Vamp start" looks to be your best bet if you want to start as a vampire. That build will give you a 20k acres kingdom with 18k BRT buildings. Then you spend the next 500-1000 turns after leaving NPP offering for more land, and building the types of buildings that you'll need. Your BRT will be very high, so you ought to end up in the 40-50k fully built area.
A kingdom like that can take down the smallest NPC, then you build a bit more, and work your way up the list of kingdoms. If you run out of turns, go to the bounty screen and claim the turns from the kingdoms that you've killed. You'll get those turns and can use them to continue climbing up towards Nymphsongs King.
On another totally different tangeant, while looking through saved builds, I just found a MAJOR exploit. OMG I got some fixing to do lol.