Cut your grass. Unless it is clumpy, the clippings should not bother the new grass. Leave them on the lawn if possible. The are good organic matter and help fertilize your lawn. Just be careful when making turns with the mower. As for the weeds, just cut them along with the grass and deal with them later. It's too early to use herbicide. When you plant in the fall, be sure to kill the weeds several weeks ahead. If you use a selective weed killer, pay attention to how many weeks you have to wait before planting. It may kill your clover; read the label. If you use glyphosate, it will kill everything it touches. Spray then start watering lightly to encourage weeds to sprout. Then in a couple weeks right before seeding, spray weeds with glyphosate again. See if you can find a starter fertilizer that has mesotrione in it. It is a short term pre-emergent that can be used at seeding and will allow your grass to get a head start over the weeds. There also isn't as much weed pressure in the fall. Good luck!

I forgot to mention: watering is going to be very important to keeping your grass alive. I suppose you have done the light, frequent watering that is done at seeding, gradually reducing frequency and increasing amount. Try to increase the intervals between watering, so that you end up doing deep infrequent watering, at least while the grass is still growing. But at the same time, be alert for signs that the grass needs water. If it does, water it. Your grass will have short roots and the summer heat can easily do it in. If the leaves start to curl or if they change to a duller color or if if doesn't spring up after you walk on it, it needs water asap. When the grass growth slows in the summer, go into survival mode and water frequently enough to keep it alive. In the fall return to deep, infrequent watering. Hopefully you will have long roots by the summer of 2018.

For your early fall planting (aim for mid August), you don't have to use a dethatcher or aerator. You can if you like and just one would do. Raking like you did will rough up the ground enough. If you use an aerator do it early enough so the holes have filled in by the time you seed. The seed needs to be on top of the ground, with just the barest bit of topdesssing (or no topdressing). Before you seed cut the grass/dead weeds as low as possible, bagging the clippings. After you seed, keep it moist with frequent light watering. If you don't have irrigation, figure out hoses and sprinklers and a timer so that you can water several times a day at first. After the seed germinates, you can gradually reduce the frequency and increase the amount of water. I'm not clear on whether you plan this as an overseeding or a complete renovation. If you plan to kill everything and replant, it doesn't matter whether you keep the spring planted grass alive over the summer.