welcome to BW and congratulations on your lo!! Couple of questions. Was your lo born to term or a preemie? How much did she weight, how much does she weigh now? Any medical problems (reflux, etc?) Is your lo swaddled?
To answer your questions as best as I can:
1) it is common for very young babies to have an evening period of fussiness and be awake for a while (commonly called the "witching hour") It is possible that your lo is OT and thus not settling for naps, too. It may take a while for her to come down from all the excitement of people being around. But, at this age, 1.5 hr A time (A time is ALL awake time, from the moment they open their eyes from nap/sleep to the moment they close them again...so this includes eating as well!) can be too much! The first yawn can already be too tired. My lo's awake time was only about 45-50 min for the first 3 months!

So, it may be awake, feed, nappy change, stare at mommy for a minute, and right into your wind down.
2) If she has skipped a nap and you feed her put her right back down. If you've been trying for a nap for 1 hr and especially if she's been crying the whole time, stop, feed her, then go right back to putting her down. If you ever get a short nap (anything under 1 hour) then the following A time needs to be reduced to prevent over tiredness. Make sense?
3) If she has gone 3 feeds with no naps then do what we call APOP (accidental parenting on purpose). At this point she's probably WAY OT (overtired) and needs some serious help to sleep. So you can try a walk in the stroller, baby carrier, swing, car ride...basically whatever you have to do to get her to sleep!!! Like I mentioned before, the first yawn may be too late at this young age.
4) Cluster feeding is up to you. Some lo's do well with it, some don't. My lo didn't do well with it because he has reflux and that much milk that close together just made him spit up. It's all trial and error and finding what works best for your lo.
I hope that helps you out a little bit. Feel free to keep posting any questions, that's what we're all here for!!! Remember to rest when your baby rests, take care of you, and enjoy her because they grow up SO fast!!!