I also use have used Cokin ND filters over the years and have had no major issues.
CPL Hands down, there are several other means of gathering GPS information.
I have use Cokin over the years. The star burst and ND's mostly. I do not use them that often.
The 28 - 300 is a great lens but is not one that I would consider using a TC on. I do use a Kenko 1.4 TC on my 70 - 300 Nikor and 150 - 500 Sigma with no problems.
The second one excellent shoot.
I have a Df and it is great in low light situations as long as you have no interest in video you may want take a serious look at the Df.
I would take a 28 - 300 for just a day of pleasure shooting. You basically have everything covered. I was not a big fan of these telephotos until I saw the results of what a National Geographic photographer accomplished.
I shoot manual 99% of the time. Once in a great while I may shoot shutter priority.
I love my Df no flash no video it does what a SLR was meant to do. I wanted to shoot video I would buy a video camera.
I seems to depend on where are. Any where around play ground, parks, or other areas where children are I consider a No No completely off limits. Buildings, carnavels, fairs, boardwalks ect. are fair game to anyone. I live in the Gettysburg a tourist area and it gets share of some real weirdoes, some do not know that the Civil War is over. Oh well it is what it is today.
I rarely use a cameral strap but when I do it is a Tamrac quick release. CherylZ I should have taken your instructors camera course. Back in the 70's I had a camera hit the floor when a child pulled it off a table by its strap. The lens had to be repaired.
I set mine to cloudy but shoot both Raw and JPEG. I am wondering about the setting it to cloudy.
I sold all my film cameras last summer went totally digital. I do believe that film produces a much finer picture but getting film and processing labs are much harder to come by these days.
My State Representative supplies inventory books to keep a record of firearms. I have a couple of copies that I converted to use for my photographic equipment. Their free and work great.
During the forty plus years of photographing various subjects under varring conditions I have never used a filter except for CPL. None of my lenses have ever been scratched nor scuffed. Now that we have come into the digital age and the corrections that can be made through photo processing I really do not see any need for the use of filters other than a CPL or ND.