re 2) Other than the specific features related to a certain module type: survey, construction, trade, troops, carrier modules the best orientation IMO are hull sizes. These need construction techs (like in GCII), just watch out for those which unlock "medium" "large" etc hulls. Usually when you are able to research the tech you get the result on the left of the display.

Of course it does not tell whether you can build a specifically equipped ship since this depends on the weapons, defences, and other modules available, so does not depend on one tech alone.

Being new to GalCiv 3 and only starting playing I have gathered that the game uses two different kinds of "move/speed". First you have the strategic moves, where your ship can move a certain number of tiles per turn. This might be called moves or speed - the associated ship components are usually providing 2-8 moves - multiple components stacking to provide the ship with engine component x number = total strategic ship moves.

Second the game also use a term 'tactical speed', which is used during ship battles to tell how fast the ship moves. Faster ships means shorter time before engaging with the enemy (I think). Or at least I think that higher tactical speed is a good thing in combat

As others have said, the game features ship designs. This means that you can design /make your own ships e.g. blueprints. For example you could make a ship full of sensors components creating a "sonar buoy" instead of using the standard ship design for the specific race. This also means as you progress through the tech tree you will unlock more and better components to be added to your ship. However the ship designs are usually limited by the hull size of your, which are divided into tiny, small, medium, large and cargo. Larger hulls provide more space for components meaning you can pack more weapons, defenses, support, engines etc. onto the ship. The hulls tech (orange/brown) are found in teh Engineerng branch of the tech tree.
 

You can choose a tech farther down the tree and the game will research the intermediate techs. However it is not possible to choose multiple different tech from different branches and queue them up.

4) I'd like starbases explained - where are resources explained? Are there tutorial videos on game mechanics? 
Star bases are used for expanding your area of effect. Further they also provide various functionality. As said above, the star bases can provide planetary bonuses, provide access to (strategic map) resources /relics or serve as an anchor for military or cultural expansion. At the start of the game your star bases can be go into military, cultural or mining. 

Military means a military star base with better weapons and defenses - kind of like a border posts. Cultural star bases serve to expand your territory by generating influence/cultural points (think Civ4), and with enough influence you can overwhelm your neighbours. Mining provides access to strategic resources e.g. durantium, thulium etc. marked on the map. Each of these resources provides access to special ship components, prototypes. For example Durantium provides access to a better hull with increased hull (hit) points, while antimatter provides access to an advanced form of missiles (yellow weapons). 

In addition the star bases can also give access to relic (using Xeno technology - found under the manufacturaing branch - i think), where different kind of relics provides different bonus. Some relics provides an overall boost to approval, manufacturing, research etc. Other relics are necessary in order to achieve an ascension win.

When you have progressed further down into the tech tree you will also get the option of expanding your star bases with planetary bonus modules e.g. planets in the star bases area of influence will receive a boots economy, research etc. Star bases can also be equipped with modules modules making ships faster or slower in their area of influence. Last but not least the star bases area of influence can be expanded as well as their sensor range (the area of the map shown).

In order to construct you need a ship with at least one  constructor module - usually named 'Constructor'. A ship can have more than one constructor module making it easier to add to modules. One constructor will construct a star bases, while additional constructor modules at that star base will construct modules - the modules being the ones described above. Therefore it is often a good idea to make ships with two or more constructor modules. Further idealogy also provides a skill giving two constrcutor points for a single constructor component.

I believe moral is the same as approval (happiness), culture is the same as influence, military manufacturing might be the half of normal manufacturing and only applied to ship yards, food is equal to population limit. Further each planet has a number of tiles/hexes, where some hexes have adjancy bonus. An adjancy bonus provides a bonus to a specific to manufacturing, research, income, influence or tourism improvements (buildings).

Each planet has a population number, which is divided between manufacturing, research and income depending on the empire/planetary slider. This is defined as raw manufacturing, raw research or raw income. To this raw XXX you then add "multipliers". For example a basic factory might provide 35% multipler to the raw manufacturing. With 10 raw manufacturing the planet would yield 13.5 manufacturing points. A basis factory placed on a tile next to another tile, which provides +2 to manufacturing, would increase the basis manufacturing mutiplier with additional 2x5% = 10%. 

As I am relatively new to this game, please correct any mistakes I have made.

I am having the same problems. The answers really need to be IN GAME, a tutorial would be barely sufficient but better than nothing.