Let me add my humble opinion.

I would find switching lenses a nuisance. I was quite happy with a 18-135mm lens until I encountered the situation which, for me, occurs often, where I wanted an 18mm and over 200mm at the same event. I now use a Sigma 18-300mm "zoom" much of the time. However, the 18-135 should cover most of your needs. Be advised there are 3 different types of focusing systems. Both of the newer ones (STM, USM) are OK.

Also note, many "kit" lens packages offer the longer zoom (70-200) WITHOUT image stabilization.

Regarding the 55-250mm lens... I looked up Canon EF 70-210mm f/3.5-4.5 and it appears to be a lens from 1990 with USM focus drive (good), but without Image Stabilization (bad). I have no idea it's image quality. But the EF-S 55-250mm f/4-5.6 IS STM has pretty good IQ and is considerably closer focusing (able to do .29X magnification, compared to .17X mag with your lens). The STM focus drive is smoother and quieter than USM, but might not be quite as fast. With telephoto lenses such as this I.S. can be very helpful, especially when using the lens on an APS-C crop camera such as the T7i. Yes, either lens will act as a 1.6X more powerful telephoto on T7i, than they would on your old film (i.e, "full frame") camera. Of course, the EF-S lens won't fit onto your old film camera. The T7i, on the other hand, can use both EF and EF-S lenses equally well.

I've been using Canon I.S. lenses for over fifteen years and am a big fan, especially with telephotos... So, yes, I'd recommend getting the kit that includes it, so long as the price is favorable ("kit" bundles usually are a good deal.... but you can check the difference the lens adds against buying it separately, to be sure).

Another lens that's sometimes bundled with Canon cameras is the EF 75-300mm "III" (non-USM, non-IS). I do not recommend it. It's Canon's least expensive telephoto zoom and also one of their worst. The 55-250mm is a much better lens in many ways. It's usually a little, but not a lot more expensive than the 75-300mm... but well worth it!

The camera will most likely come with an EF-S 18-55mm IS STM, too... which is a decent little lens that nicely complements the 55-250mm. Neither of those lenses includes a lens hood. I'd recommend buying the matching hood for both of them. Canon's OEM hoods probably cost around $25 apiece... But there often are also cheaper "clones", such as Vello ($12-$15 apiece) that likely do the job just as well.

You likely won't need that old Sigma 28-80mm... which is probably a good thing. Even if it worked well on your old camera, there often are compatibility issues with old third party lenses on newer cameras. Sigma has probably had more of those issues than any other manufacturer. I have an old 28-70mm Sigma that worked fine on Elan 7E, EOS-3 film cameras and 10D DSLR... but causes 30D and later model DSLRs to lock up with error codes. Thankfully, I bought it used and didn't pay very much... it's not fixable.

It sounds as if you've seen some bundles that include a whole lot more stuff. BE VERY CAREFUL. There are a lot of bait-and-switch shysters on the Internet! I recommend sticking with the reliable vendors... such as Adorama, B&H Photo, Amazon Direct, and a few others. The long-established stores are far less risky than many of the fly-by-night outfits on the Internet. Whoever you decide, ask here or check them out thoroughly in other ways, before giving them your credit card number!

The manufacturer assembled kits are great. And the reliable stores put together bunbles of reasonably good items, too. But the Internet shysters but a bunch of worthless junk in their kits... sometimes even swap out quality items that were originally provided by the manufacturer for cheaper junk.

Have fun shopping!

I have been following UH for 1-2 years now. It has been a great resource and I have really learned a lot. (That being said, due to my limited knowledge I sometimes feel that I walked into the middle of a French movie and start looking at feet for the subtitles). I am familiar with photography having owned an EOS Elan IIe. Wanting to move into the 21st century, I'm looking at pulling the trigger on a T7i. I still have a Canon EF 70-210 3.5 to 4.5. I know that as it's a full frame lens it will equivalent to a 105-315 on the T7i. I know that it will work on my new camera but I'm still thinking of getting a kit that also has Canon's EF-S 55-250 IS STM. Does this make any sense or should I skip the 55-250? (I also have a Sigma 28-80 3.5 to 5.6 but when I attempt to manually focus, it sounds like someone trying to go from 2nd to 3rd without using the clutch.)

Second, many of the kits from A,B and C also contain other equipment, bag, filters, tripod, etc. Now I know that that these are probably not the best quality, but my thinking is I will need most of this stuff anyway and this is a painless way to get everything all at once. I figure once I get deeper in the weeds I can figure out my needs and replace what's needed. So my question is does it make sense to get one of these all in one kits? Your opinions would be appreciated.