Hi, and welcome to the forum. No question is too easy, but many are hard, mostly because we can not visualize it. That said, please remember my advise is without seeing it, and may be incorrect based on teh actual circumstances. Also, things here are read by others, and they must understand these limitations.
Luckily, you don't have a large area. If it was a larger lot, I would be recommending a new meter, one dedicated to your irrigation needs, and sans sewer costs. In your case, the small area needing irrigation does not warrant this. You did not specify how much of this aa is turf, vrs. beds. If it is mostly beds, drip is the best option, and write back for suggestions. For this discussion, I am assuming mostly turf.
Disclaimers done.
Your second post probably has the best option. I suspect your hose bibs are supplied by 1/2 (copper or PVC). Your velocities thru 1/2 schedule 40 PVC must not exceed 4.22 ft/sec, or 4 GPM. I know they now give you more, but they are not flowing at maximum rate to a distant valve. If the supply to your 1/2 in faucet is 3/4 PVC (all calculations based on schedule 40), the maximum velocity is 4.81 GPM. Exceed these velocities, and you will have waterhammer to deal with. You will also probably experience some internal plumming water flowing noise in the house so be aware of that if your home contains light sleepers.
So the best option is going for the 3/4 tap and run he PVC around the house. Your still should not exceed the 4.81 GPM velocity.since it is going thru the house. You mayexperience an increased pressure. Best to test it after you make the tap. Again, do not exceed the 4.81 GPM recommondation !
Since you have a relatively short distance to run the PVC to yor manifold, 3/4 inch will suffice. Over 100 feet of 3/4 PVC at the permissable velocity you only loose about 5 PSI. You are going 50 feet, so it is about - 2 1/2 PSI.
So your loss to the manifold counting fixtures, will be less than 3 PSI. Increase the velocity (more GPM) and those pressure loss number increase and you would consider up sizing your pipe for longer runs, with higher flow.
Now, with only 4 GPM, your choice of heads is limited, unless you want to have a lot of zones = more $). Again, the lot dimensions are not specified, but its relatively small size lends ne to believe pop up sprayheads might be your best choice. I suggest you strongly take a look at MP rotors, which perform very well, are adjustable, require low GPM flow, fit on numerous heads (including my favorite the Rainbird 1804), more efficient than sprays (larger water droplet = less loss to evaporayion and wind drift) and are fun to watch work. You will be able to put more heads on a zone, saving by not installing more valves,pipe, wire, and a bigger controller. All, and Weatermatic Valves are available from this sites sponser at a good price (
www.sprinklerwarehouse.com). I recommend them and receive no consideration for the endorsement. Recommend Weathermatic silver bullet valves with flow control. Work well at low flow rates, and are easy to clean if necessary. Also have internal manual bleed, so when turning system on manually, your valve box doesn't flood with water.
So, KIS, go with 3/4 inch throughout (saves money on fixtures if uniform size throughout), Weathermatic valves, 1804's, with MP rotors. And, did I mention MP Rotors?
Good luck, and if my assumptions are wrong, write back for more. Jeff