@Sangam Baligar welcome and good luck to you. Before your read any further, I would not consider myself an expert, but I do think based upon your post you and I are probably in the same boat.
I assume if your budget is 400k, you probably have 80k-100k liquid cash for deal 1? Here's my advice - lower your budget. The first property you get will have closing costs and need probably several thousand dollars in a "general fund" to fund your advertising, maintenance, unexpected CAPEX, initial vacancy, etc. Don't spend every dollar you have in property one, if you can help it.
As @Michael Lee indicated, if you have 400k sitting around, your options drastically change. You should be investing perhaps in a small community of properties or maybe several triplexes. And speaking to an investment consultant of some kind. 400k liquid cash makes you a pretty big fish, I would think.
As far LLC/personal, I've seen a few people comment that its up to the buyer. Sure, but an LLC has different rules and may qualify you for a commercial loan, which might raise the rate. To me, on property 1 (and every property thereafter), I want the best possible terms. You might want to start with a personal loan and then slide it under a LLC. I have a great mortgage guy I just used who might be able to better explain the rules to you.
As far as FHA/conventional, I have a VERY strong opinion about this. if you're only holding for 5 years, go conventional. Why? Because your cash flows with a conventional will be better (no PMI, lower monthly payment) and you will gain equity in the property faster, which will net you out money when you sell. The only way I would do FHA is house-hacking where I didn't have much money to begin with. FHA sounds wonderful in the beginning until you're paying 100 a month or more in PMI (that's -$1200+ to your cash flow for an investor where your chances of default are low) and you have no equity in your property and you want to jettison after 5 years. Those FHA loans are front-loaded with interest and nobody thinks about that.
Regarding the Philly area, @Jason D. makes great points as always. I think that a lot of the areas are saturated right now, so look for low-tax, outlier areas with close proximity to Philly. I just purchased my first property in Gloucester City, NJ, and time will tell if it is a good investment.
Good luck and let us know if you have more questions.