Hi Puffdragon! Thanks for your questions.
Its always hard to display enough info on a mobile device without it looking a mess, as such some of the display for things have been simplified. To answer some of your questions:
1. Reload speeds are completely individual for each turret, the name is purely a guide.
2. You can view the description of the max upgrade for each turret by pressing the buy button again in the armoury even if you own it.
3. Colossus damage charges above the base damage value, making it much more powerful than is shown by just the number if it can attack a single target for long enough. A maxed colossus will also charge to maximum power much more quickly, making the total damage per shot far greater than an equivalent non-maxed version.
I hope thats some help 😉