You can reach your ship class fairly quickly. It does take some time to level up to reach the tier 5 ship. Playing other ships while leveling up does help you learn their over all functionality. Which in turn helps you when fighting that class of ship.

I believe they have already reached their current limit. However they will be sending out more invites throughout the beta.

Just log out if you are in the game and log back in. If you were awarded it, you should see it added then.

These are the exact ships and builds that Captains use throughout the Dreadnought lore.

Not sure if this one has been mentioned. When you join a game in progress, you are missing your recticle. The players are missing their details above their ships. So you can not tell who is friend or foe. This does correct after you die. But even after dying it some times locks the score so you can not see who is winning or losing unless you access the menu by pressing down on the D-pad.

Are you purchasing them after you research them? Have you tried adding them when editing the ships loadout? You may want to remove your e-mail from your post.