Is that a good decision? Will I need the 18-55 lens?

It depends on several variables:

• The price difference between the body only and the body + kit lens. Often the difference is negligible and not buying the kit is almost like turning down a free lens.
• Whether you will need or use a lens such as the 18-55mm f/3.5-5.6 kit lens. Such a lens is very useful for many situations. That's why they are so popular as kit lenses. But that doesn't necessarily mean you will find it useful. But then again you might!
• What other lenses you plan to buy in the near future. If, for example, you are planning to buy a 17-55mm f/2.8 lens which is usually a higher quality and more versatile lens that covers everything the 18-55mm f/3.5-5.6 can do then buying a kit lens would be superfluous.

Will these two lenses cover all types of photography?

No two lenses will cover "all types of photography". That's why Canon and Nikon sell hundreds of lenses for each of their systems. The lack of such a broad selection of lenses is partly why other camera makers sometimes struggle to gain market share even when their cameras may offer more or better features at lower prices.

The 70-300mm f/4-5.6 will do OK for sports and wildlife in bright light. But if you want to shoot sports inside gyms, sports outdoors in the early morning or late afternoon, or night sports under lights you'll quickly find that you need a lens with a much wider maximum aperture to allow you to use shutter speeds fast enough to freeze the action. The same is true of early morning and late afternoon when many types of wildlife are most active. You'll likely need a "faster" lens to get the shots you want.

... such as fashion blogging and family get to together for example?

On your D3300 with an APS-C size sensor, the 50mm will do well when you have enough room to back up to get the framing you want. If you are indoors in a typical family residence you'll probably find that you won't have enough room to back up to get any group shots of the family. You'll probably find a 35m, 24mm, or even an 18-55mm lens combined with some type of flash to be much more useful in that situation.

Do you think the D3300 is good enough to get the most out of these lenses?

Not many cameras are capable of "getting the most" out of any lens, since there's almost always a better camera that can get just a wee bit more out of the same lens. Certainly no entry level camera would be considered as such. The personal decision for you is how close to "the most out of these lenses" you are willing to consider as "good enough" and how much you are willing/able to pay for it.