I agree with HandyMac. You can just buy any oil-based varnish and thin it 50:50 with mineral spirits. This is a more cost effective way to go if you are doing a number of projects. Be sure to stir well and often if you are using anything other than a gloss because the flattening agents will quickly fall out of suspension. If you have some mineral spirits (paint thinner), wipe some on your wood. This will show what it will look like with a few coats of varnish (without stain). It will evaporate away in a little time. Adding a lot of water to a water-borne finish is not a good idea. It has a delicate balance of chemistry. There are very few people at the big box stores that I would trust to provide accurate and good information on wood finishing. You will find an occasional diamond, but most of them just know paint and how to mix it. That's being generous, some of them just transferred from plumbing supplies or home and garden. I am not familiar with Wood Sheen so I looked it up. It is a gelled, colored varnish. Minwax are experts at marketing and obfuscated labeling. As appealing as a "one-step" finish is, it's a terrible idea. If you do manage to get a non-streaky finish (which is difficult), it will likely be too thick and opaque. As far as 'gelled' finishes, you _want_ the finish to soak into the wood. Gel does just the opposite. Would I use it knowing what I know about it now? Never. (I am a professional finisher and touch up person and regularly teach classes in wood finishing to woodworkers, so I can use any finish available. I still would not use WoodSheen).

I think if you restain one, you’re gonna have to restain all. Try to patch it up on that spot. If you only stain that one it might look darker and newer. Since your cabinets are 8 years old, have sat through some sunlight and are not going to be the exact same color as when you first bought them, don’t restain just that one cabinet.

If you use a solid color stain, you could put a sealer just over the nail heads or screws, whichever it is, so it wouldnt bleed through. A different type of nail or screw should have been used, so it wouldnt rust, and look like that. It will look very nice, once you stain it.

I think you should try to match the rest of the bedroom furniture. However, getting colors to match can be difficult, because the wood of the desk may be different from the wood of the dresser which affects the Final Color. Moreover, even if the wood is the same, you don't know what color stain was used on the dresser. I suggest you use a gel stain which is thicker and less likely to drip and run. Start with a medium brown similar to your dresser. Check the color on the back of the desk for an idea of how it will look overall. Wipe off excess stain and let it dry. You can add a second coat if the color is too light, but be careful not to end up making the desk darker than you want. Note that I do not think all wood furniture in a room has to match. That is because wood is, to me, a neutral color. The pieces below are reddish-brown, dark brown and painted, but they work together because they are all have a similar classic design. The furniture design below is a mixture of styles and ages. Some of the wood is natural and other pieces painted.