First question. Normally one has 2 weeks vacation per year. One month every 2 years is then normal. But they give you 2 months vacation, one will be paid, the other no. As if you would be paid 700$ a month on vacation.
Second question. So you will have one year with no vacation, the other year with a long vacation. Every 2 years you will have 2 months off, one of which will be paid 1400$. Why not vacation every year? It is not logical.
Third question. Yes only one ticket every two years. This is normal. If you have family, some companies will pay for your children. It is negociable. You have to add your 1400$ of vacation pay to the price of the round trip. If a round trip is 3000$ the employer will then have to pay you 4400$ for these two months vacations. Last question. Normal, but everything is negociable and up to you.
Should you sign? Investigate first who is your employer. A company or a lone guy who could go bankrupt and leave you in the cold. Is your employer a financially sound company?
What about the working permit? What will he do to legalize your situation? You also have to know about tax issues. What is the amount after taxes? What about your income tax in that country and yours? Who will help you with the tax forms? There are a lot of questions that need to be answered before signing. Where will you live? Alone or in a dormitory? If you are sick? Any insurance ?
May I suggest checking this website for international jobs in culinary arts. It could help you decide before signing a contract. Once you are in another country, there are a lot of things that can go wrong and you need to be sure your employer will be there to help. I had bad experiences and good experiences, so investigate very well before signing.