We got approved for a conventional loan but don't have the 20% down we need for an investment property.

All conventional, fha, and va loans will get sold multiple times. 

Conventional are less stringent. 

Dividing it up that way maps it closer to max of 1-2 week stay per year per owner (for average typical timeshare convention) and makes the ownership cost more affordable than it is now at 1/8 share, especially the more pricier listings for the multimillion dollar homes.

Is the rate typically the same as conventional loan for investment property?

Conventional loans are the only conforming residential product for non-owner occupied. 

I just spoke to a lender and he said the interest rate is usually 5% for 30 years. 5% x 30 years doesn't seem all that great considering interest rate for a conventional loan is at an all time high around 3%. 

you need to slow way down and have a clear picture of what you're getting yourself into. as others had mentioned, why not go the conventional loan route?

My question is this...I have enough saved up for a 20% down payment - however, I was thinking about using an FHA loan for my first property (and living in it) and then start looking to purchase a second multi-family home shortly after with a conventional loan and 20% down.

It's basically a garage/storage area, but could be converted into a legal home/livable space.If we were to purchase the property through a conventional loan and convert the 2nd building, is it fair to assume we could then refi at a higher property value?