I'm not exactly the most experienced guy around here, but here goes:
600-700 AIP is pretty high. Some people super lowball it, like sub 100 for the entire game until they hit the homeworlds. Others take the entire galaxy every time they play. I've only won a single game, and it was around 300 AIP at the end. But that's mostly because I don't play tons. I have 2 games going right now, one is at 500 AIP and I'm taking everything in sight. I think I've hit the point where I'm unstoppable in that game. The other is Fallen Spire and I'm at around 150 AIP 8 hours in, preparing to build my first city hub.
1a. It depends. Every planet you capture gives you an energy collector, resource income, and knowledge. At some point though, you'll usually want to skip a few planets to secure something more important (like an Advanced Research Station, Fabricator, or Advanced Factory). However, the extra energy can really help if you take a lot of planets because it's hard to keep everything alive at times.
1b. Kill everything but the command station, then ignore it for the rest of the game.
2. Reinforcements show up at Guardposts and Command Stations. As far as I can tell, killing Guardposts DOES reduce the number of reinforcements. Killing Command Stations will put adjacent planets on alert (making them spawn stuff).
3. Without any Guardposts, yes. It will still gain reinforcements at the Command Station. However, the reinforcement numbers are capped on a per-guardpost basis. Without any guardposts, it's unlikely for them to get a large enough force to trigger "border aggression".
4. During normal waves, no. They just spawn out of thin air. Warp Gates can spawn full sized waves by themselves (there are even "Warp Gate Guardians", which can spawn waves in your territory if they're attacking you when the next wave is announced). However, during Cross Planetary Attacks, ships are taken from the galaxy. I think it's something like 50% of the ships are taken from the "Strategic Reserves", most of the rest from Barracks, then the rest is just taken from kind of anywhere.
5a. Gravity Turrets, Riot Control Starships, Fortresses, Miniforts, Flagships, Forcefields, Hardened Forcefields, Heavy Beam Cannons, Emp Mines, Area Mines, Spider Turrets.
5b. In the current betas, no, Mk. III-IV fleetships aren't worth it (because starships are currently OP in the betas). In the last official release (6.0, most of your starships will have unit caps of 4), yes, absolutely.
6.
Quick and dirty overview:
Economic command Stations give you the most resources, so you can build more attacking units. The extra energy is also handy since it will allow you to afford a bit of extra stuff like mercenaries.
Logistics Command Stations make your ships move REALLY FAST on that planet (it has an extra speed boost that isn't listed in the tooltip), and it will also slow down enemy movement (allowing you more time to respond to an enemy attack against it). If you have to move your fleet around a lot these really help. Also worth noting, the Mark III prevents enemy ships from teleporting, which is situational, but really useful. All Logistics Stations have Advanced Warp Sensors built in, so you can see which wormhole an incoming wave is going to come through, allowing you leave them a nice welcome present, like a warhead or three (the wormhole turns yellow on the main screen, you might have to zoom in to see it).
Military Command Stations are tougher, they have Tachyon Coverage (stealth detection), a Planetwide Damage Boost, and the railguns. The Railguns on a Mark II Station cause engine damage in addition to knockback, allowing it to hold off way more ships than a Mark I. Mark III Military Command Railguns also Paralyze enemy units (in addition to knockback/engine damage), allowing them to single handedly render a force of 300 or so ships useless. Mark III Military Commands give you Planetwide Tachyon coverage, so you don't need to bother with other stealth detectors on that planet.
I've never used Warp Jammers, so I'll let someone else handle those.
In general, all 3 types of command station are useful. You want your borders to have either Military or Logistics, and most of your less important worlds with either Logistics or Economic. Logistics 3 and Military 3 are both very powerful for defense if you unlock them. Unfortunately, you usually can't get more than 1 maxed due to high knowledge costs.
7. I like to think so. It reduces the number of special forces, which makes taking out Core Shield Generators easier.
8. Fortresses can do it, Military Command 3 can do it (up to a point), a ton of turrets can do it, but in general, no. You'll have to pull your fleet back unless you're playing a low AIP game. This is where having "extra planets" comes in handy. You have a few turrets and miniforts on each, and they'll do a bit of damage before they go down.
Mining wormholes can be very effective. I like to place mines around a wormhole, something like this, but centered better, with the fat end facing the command station. I zoom in super close and put them as tightly packed as possible.
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It'll help some, but won't kill entire waves.
9. Build a bunch of transports, put your ships inside, fly up to a guardpost, unload, kill it, rinse, repeat. If the eye is something really dangerous (like a nuclear eye), you can scrap your fleet to stop it immediately. You can also use starships. For Spire Shield Posts, load up the bombers, they get a big damage bonus against them. Spire Starships also have really high DPS and are good for killing them. Also, as long as you don't outnumber the AI more than 2:1, it won't trigger it's eye. You can put your fleet in standby mode as it flies around to the next guardpost to stop it from killing enemy ships along the way.
I hope that helps!
Oh yeah, and Welcome to the Forums and all that
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