Tokina 11-16 2.8 works great with my d7000. what about sigma 17-50 2.8?

AF-S DX Micro NIKKOR  40mm f/2.8 the best prime lens I've purchased, I bought too the AF-S NIKKOR 50mm f/1.8 and is terrific, but you need to be so close if you want to make a portrait. In Christmas I received the AF-S DX NIKKOR 55-300mm f/4.5-5.6G ED VR as a gift, perfect range for me, but you're going to need many light, if you want to shot over the 1/125s; and of course a good tripod.

I purchased the D5200 with the kit lens which is really limited, it also came with the 55-300 lens, I have not had much use for the 55-300 lens other than maybe one time for a 100 yard zoom; most of the photography I do is indoors or mostly social and portrait. I purchased the 50 mm 1.8f G and is great for portrait photography if you are only focusing on one or two subjects for your composition; if you try to do groups it gets really blurry on the edges. At this point I have three lenses but I like the blurred background of the 50 mm f1.8 but I have issues with the flash trying to focus and when using the kit lens I just don't like the quality of the picture. I am considering trading all three lenses on Amazon for a more wide-angle lens, one such as the Sigma 17-70 f2.8 or the Tamron 28-75 f2.8 that you mentioned on your video, I have a speedlight SB-600 and I am looking to do some group shots (10-15 people), some outdoors and portrait photography; I would like to have a lens that is flexible for these activities but I don't have much money to spend. I know this is a loaded question, specially because I am a beginner and I would like to start taking better shots.

I am looking into purchasing a Nikon D7100 along with the 18-140mm lens. I like the versatility that the 18-140 will offer, even though I realize it is not the fastest of lenses. In going with the D7100 instead of the new D7200 (which the added benefits don't seem like important benefits for my needs), it allows for a little more room in my budget for a prime lens to add to the mix. (I plan on buying these all used from Ebay or the like). However, I'm trying to decide which prime lens to get. The 35 seems like a good walk around lens, but the 50 better for portrait. These are 2 areas of photography that I enjoy the most. I am often in a confined space however when doing portrait work since I don't have a studio or anything (just a hobbyist). So now, I'm thinking that maybe I should decide between the 35mm and the 40mm. I do love the occasional Macro shot and the 40 would get me a range between the two.