Dezmin,
Generally speaking for REI properties, if you are purchasing it as a 2nd home you can qualify for a residential mortgage with as low as 10% down. As far as having all of your names on the mortgage, I would speak with your lender about that but be wary! You should structure your partnership with your friends through a RE attorney who can protect your interests and have it written down as a legal document. I've heard way too many stories about my investor friends getting burned in partnerships with family and friends where the business or personal relationship turned sour. You all need to be on the same page with respect to your short and long term investment goals, property management and marketing strategies, maintenance, and ultimately disbursement of profits.
With respect to placing the property in an LLC you can find several arguments for/against this in multiple BP forums. The skinny: LLC's offer liability protection which comes in handy when you have an extensive portfolio, have a large equity stake in the property, or are trying to shield large amounts of personal wealth. However, they can be expensive to establish and maintain and might not be worth your time if you have limited equity in the property and/or if this is the only property in your portfolio. Also, keep in mind you can't refi a property that is deeded in the LLC name (at least not in my state of TX, but consult with your attorney). The deed has to be transferred to you and/or your partners in order to do this.
Ultimately, I would seek legal counsel to best structure your partnerships and whether or not an LLC is in your best interest. Lots of ways to skin a cat, but this is just my 2 cents.