I have a Sony a6000 and an a6300. If you are concerned about money try the a6000. It's a great small camera as all three of the Sony's are....the a6000, a6300, and the a6500. Just depends what features you want.

Look at dxo. They rate the a6000 as one of the top crop frame cameras. I own two of them and a 6300. In the stories you'll be using a kit lens and that lens is not known for being high quality and varies on the copy you get.

Post wedding pictures can be a problem since you don't technically own those photos in most cases. If you are going to use the photos from self-promotion, then it should be in the contract. If you are going to use them for anything you want, it should be in the contract. But, then again, just because you can do it....should you?

I've stacked extenders and gotten good results. However, I would have been far better off with a longer lens without the extender. This is a simple matter of physics and optics. Also, there have been many tests showing the effects of extenders by people with the proper lab equipment. It's sort of like people that come up to me with a cell phone and tell me that it was as good as my gear. They have that conclusion because their picture looks great on a small cell phone screen. Extenders do a very good job but it's not the same of have a lens with that focal length.

Lightroom has Adobe camera raw built into it.

CHOLLY: What camera did you have?

My point is we don't know much about this camera. Until it proves itself in the field it won't receive a following from professional photographers. I shoot for a couple of newspapers. I need to know that a camera will hold up and not just physically. What is the quality of pictures under all conditions. I have Sony mirrorless cameras. One of my biggest problems is keeping that sensor clean. That might be a problem in the field with this camera. We don't know. A lot of things we don't know about this camera and actual performance. It may turn out to be the greatest camera ever made. My point is it has to prove itself first. And we need to know that we can get the assessories and equipment for it. That will come with time like it has with all the other cameras.

Durability and reliability are critical issues in a camera. Sony hasn't a proven track record as of yet like the big two. Nikon and Canon have proven products that are also full supported with lens and accessories. We'll have to wait and see.

This is not an uncommon practice. Usually it just that the event want their photographers to take official photos with quality equipment. It's more about protecting their brand than anything else. Many events a have the "dollar" rule or some comparable. The length of you lens can't exceed the length of a dollar. I was turned away from a regular season college softball game because of my 24-70mm lens. So now I just take my Sony a6000 with me rather than my 5d or 1dx. However, I still follow the "dollar" rule with that camera.
Set back and enjoy the race with a small bridge camera that has a 52x electronic zoom before they ban that one too.

You have great equipment but I would really recommend that you DON'T do it. Weddings are not a place to practice. Also, by doing this you are putting professional photographers out of work.
Having said all of that, if you must. Make yourself a shot list. Try to get as many candids of the guests as you can. That includes any meal they have served. You might be able to get a quick bite but don't count on it. Do formal photos of the bride and groom, best men and bridesmaids, the families, etc. Let everyone know when they can expect the formals to be taken. Informal of everybody. Remember you will see different activities going on at the same time. Wear comfortable shoes. It's going to be a long day. Get pix of the bride and groom arriving and leaving. Of, course the bride and groom getting ready. Sometimes you will have to be in two places at the same time. Shoot pictures of the rehearsal. This is for documentation as well as learning the light for the area. BTW: it probably will be a little different during the actual wedding. Important: ask the priest, minister, rabbi what the rules are for photographers. Some don't allow pictures during the ceremony at all. Flash may be questionable. You need to be as invisible as possible. Also, know your time frame. If the venue has another group coming in then you may be really crunched for time. Also, find out where the reception is so you won't be surprised and can properly prepare. Keep your eyes on the head table as you are moving around for the candid shots. Don't forget the editing time. Shoot in raw. It will help you salvage improperly exposed photos. Yes, that happens to everyone.
Have a second shooter if possible. I won't do a wedding without one. The woman I use is also a professional photographer and we switch off depending on who got the gig.
I could add a lot more but this should give you a good start. Besides that others have given you advice on this site.
I would really advise getting an established photographer to do it. A side effect of getting a pro is that you would be able to enjoy the event.
The following is my viewpoint. People can spent a lot of money on a wedding but they want photos for free. Now if the cake was free, or the dress maker gave them a free dress or tuxes, I might be persuaded that a photographer should work for free. I could work everyday of the year for free.
And for the last time. I think it would be best for them to hire someone who does weddings.

Yes you can and I've done that before. I work in the news industry. The press pass is only as good as the people are willing to accept it. Every situation seems to be a little bit different. Like I said in my post, usually your news organization will issue one and then use that as proof that you work for a legitimate organization. Then sometimes you have to still get a press pass or credentials from the organization that you were covering. Sometimes they limit press passes or the type of media they want to cover. It's their choice. That's when you figure ways to sneak it.

There two types of passes. One issued by the newspaper but that does not guarantee you access to anything. It just says that you work for them. For many events you have to contact the event organizer and it will put your name on a list. When you get there they'll check the list. Then either they will just let you in or they will issue you a temporary pass for the event.

Does that happen with the cf card also?

FYI, I would never hire an assistant (second shooter) photographer that wasn't capable of being the lead photographer. People have asked me if they can be my second shooter/ assistant and I told him no because they need to have all the skills of the lead photographer. Weddings are too important of event to hire someone who still learning the basic mechanics.

Anyway for what it's worth that's my viewpoint.

As a press photographer I've never had a problem deleting in camera. I do format the cards after I submitted the pictures. I don't leave because I need to get rid of the bad shots because I'm on deadline. I can't sort through that many pictures to get to the ones I actually want. Also I have two cameras. So even if the card went bad I have the pictures on the other camera