Everything u did seems to be good so far.
When steeping grains as opposed to mashing out, u only run into a problem if u put them in temps over 170 degrees for a long period of time. Crazy scientific stuff happens with enzymes and starches and the like that can hurt the malt but at a lower temp and at the short amount of time u mentioned ur fine.
Ur correct on the hot break, its a protein thing within the wort that causes it. It works itself out after a little while. Also using the metal spoon is fine since it will be used before the stop the boil. If u used a metal spoon to stir while it was chilling when the temp is much lower i'd recommend spraying or submerging it in star san... I have a plastic mash paddle that I use and when I brew i normally keep a shallow but long tupperware container filled with a few inches of star san so I can just take them off, shake it off, use it and put it back in after use. Ive seen a few videos on youtube where people did this and so far its worked great for me.
As far as aerating, some people have different methods of getting the oxygen in. I normally sit it on me knee and rock it back and forth for a few minutes and then pitch the yeast. I used to sprinkle dry yeast straight on it but after some investigating, it appears that each of those strains have recommendations on their manufacturers website to rehydrate first. Since i found those recommendations, i always rehydrate my dry yeast. I normally take a measuring cup with the amount of water that is recommended (usually 4 oz's), microwave it fora few minutes, take it out and put some foil over the top and let it cool down to the 100ish degree temp recommended by the manufacturer. Sprinke the yeast there, let it rehydrate, stir if recommended and then pitch to the wort. There are MANY MANY MANY threads here and elsewhere on the net regarding rehydrating yeast before pitching. Look around and see what you wanna do. At the very most its an extra step in the process. This is just how I do it.
The sludge in ur strainer is fine to leave out of the wort. Its the leftovers from the boiled hops and possibly a few loose grains from the steeped bag that may have escaped. I don't use a strainer just dump the cooled wort in my carboy via a funnel and then aerate although im considering buying one, they are smart to have. As far as the high OG, it can be attributed to a few things. I've had higher then expected readings but not as high as u had. Higher readings just mean more work for the yeast. U could add some water to bring that down if it happens again on future batches but since u've already pitched the yeast, that boat has sailed.
As far as shaking the carboy or stirring if it doesn't appear active, i'd recommend against it. It may just be a slow mover and the more u brew the more u'll see that it happens and u just need to be patient. One of my first brews with a yeast starter took about 42 hours to start. It just happens.
For the airlock, vodka works or u can just use some left over sanitizer if u have it. Normally thats all that I use.
Anyway, good luck with the first brew and relax and be patient. Time is one of those things that usually fixes any mistakes we could have made. Cheers