Normally I choose Advent for the pure fact of Repulse
You're not alone; you've successfully identified the most powerful ability in the game. It was nerfed (reduced in power) in a recent patch, so that nefarious status may no longer be valid, but it remains a powerful ability.
choose my ship (Mothership for colonisation)
Good pick.
I get my fleet maxed out straight away with Disciple Vessels.
Now, I understand where you're coming from, but I honestly don't recommend this. Sins uses a "rocks paper scissors" counter system, meaning if you build too many of one unit type you leave yourself vulnerable to its counter. I strongly advise to diversify your fleet early and don't lean too heavily on the light frigate.
For more detailed advice on colonization, I refer to my guide: https://forums.sinsofasolarempire.com/363623
I research trade ports as fast as I can for the obvious fact, money.
Whether you want to go for military or economic tech first depends on your start location. Especially with normal start (you have more leeway to pursue economic strategies with quickstart) there needs to be a wide distance between you and the nearest enemy for you to safely pursue civic technology early. As a general rule, if the enemy is fewer than 7 jumps away, it's suicide to build trade ports early on. The AI will let you get away with this because it isn't very good, but a player will show up at your door with a massive fleet and knock down your trade ports before they pay for themselves.
Trade ports are, in my opinion, overrated. They have a huge capital investment requirement to become effective, as you need a long trade route (at least 4 or 5 jumps) to make them effective. Even once you have a decent length trade route, it can take 15 minutes for a trade port to pay for itself, and that's before counting the effect of upkeep. Late-game, trade ports offer you a strong way to bolster your economy, but early game they're way too expensive to set up and a good military player will show up with a strong fleet before your economy booms.
As has been mentioned, culture is a stronger investment. This is because one culture center will affect multiple planets (five or six, usually) which is very cost-efficient. Otherwise, your best economic investment is always capturing new planets and building extractors there. This also gives you strong assets later in the game.
As far as defenses go, hangers typically shouldn't be built in large numbers. They're great at chasing off small groups of enemies, but a dedicated assault force won't even flinch. If the enemy comes in numbers, your fleet needs to be there to defend your planet. No static defense in the game will stand up to a strong fleet (AI idiocy notwithstanding; it's legendary for its ability to get a massive fleet slaughtered by a modest but well built defensive line). The best defense is a bank of repair bays. These provide your fleet a place to retreat for repairs, and if they come under attack they can repair each other to buy time. This allows repair bays to stall much better than any other type of static defense. Since a good fleet will come with healing ability of its own, turrets and hangers don't really do that much.
For units, balance is the key. An illuminator/guardian based fleet with a progenitor mothership leading it makes a great base, but you need other units to round it out. Heavy cruisers, flak frigates, and carriers are great picks, even disciples with their ability to steal antimatter make great support units. As far as capital ships go, try to get a variety. A Halcyon is a great pick for swatting enemy strike craft, while a Radiance is great for disabling enemy capital ships. Rapture (one of my personal favourites) and Revelation also have their place. Advent works very well when you have all their special abilities on the field working in tandem.