Round-Up will kill grass if you are not careful... if there are not too many, pull them up by hand (easiest when the lawn is saturated - after a good soaking rain or after watering)... in the beds, Round-Up is fine unless you plan to plant seeds...
I worked for a Landscape Design, Maintenance and Construction company for five years and used to design (graphically) and negotiate lawn care contracts... best learning experience I've ever had. I always save my designs
. Here are some good guidelines from one of our proposals/contracts - this is for our Zone (I am in Ringwood, NJ):
3/01-4/30 - Fertilizer with pre-emergent crab-grass/weed control
5/01-6/15 - Ditto above plus insect control (grub control is most important - most products cover grubs, ticks, fleas, etc.)
6/15-7/30 - Fertilizer with weed control (weeds LOVE the heat - especially crabgrass.)
8/01-9/15 - Fertilizer (weed control if needed - depends on how hot it is in August and September)
9/15-10/31 - Fertilizer
10/31-12/15 - Fertilizer/Winterizer
We did a 6 application program (our customers were loaded and we figured, why not). Five fertilizer applications are plenty for the year as long as they include the weed and insect control. Store brands, like Scott's, have a five-step program I believe. You should always wait the recommended time between applications (average 6 weeks).
Lime and other mineral soil boosters can be put down any time of the year and in most cases can be put down at the same time as other applications (as long as they are watered in well).
If you have Rhodies and Azaleas I highly recommend an anti-desiccant at the least... this prevents the leaves from "wind/freeze burn". This gets applied in November.
As I said before, your lawn is going to look great this fall - you have an excellent foundation! I wish my lawn looked that good