I took a Canon SX530 with me to China. Other than the extreme cold at the Great Wall in Badaling, it performed quite well. It has one additional feature of WiFi which can get the pictures from the camera to my phone to share with family on the spot.
Is Kodak bringing back Kodachrome? For me, I will stay digital. Film is too expensive for my wife's budget for my hobby ;-)
Mine are mostly Mars Envoy. The have taken quite a bit from me and hold up.
I use and recommend the Gary Fong puffer on my Canon with zero problems. (https://www.bhphotovideo.com/c/product/1010804-REG/gary_fong_puf_pls_puffer_plus_flash_diffuser.html)
Besides a slew of Canon Rebel 2000's that I have picked up cheap from garage sales (with the lens), when I shoot film I prefer my 1976 Vivitar SL-250 (nothing automatic on that one), with threaded lenses. That's my fun camera since the internal light meter uses mercury based batteries (that don't exists anymore). The nice part of the garage sale cameras is that the lenses also fit my DSLR's.
I went to China a few years back. They were setting off fireworks, which are a lot more powerful than the ones we use in the USA. One kicked a rock that flew 50 feet right into my lens and smashed the filter (I also had a hood on and that provided no protection). That would had been the lens which cost me originally $900 and you can no longer buy now, as well as ruining the rest of my trip. Instead, I just reached in my camera bag and pulled out the spare filter and was back to shooting in a few minutes. It's not only the cost of the lens, but also inconvenience of lost time and opportunity you need to consider. The UV Filters stay on my lenses.
I have used B&H, Adorama, Roberts (Indianapolis), Schiller's (St. Louis) and Creve Coeur Camera (St. Louis) with very good luck. I would stick with these first.
I would stick with the lenses that you have, in your case, Canon. You are already invested there. I have been in that same boat myself during my first upgrade from a Rebel Kiss 300 to an XTi. I had money invested in the glass and the one camera clerk tried to convince me to change brands. After they said they would not give me very much for my lenses, I decided to stick with the glass and bought the Canon.
No thread lock chemicals for me. I always check them before I mount it to the tripods. Besides, with my luck I would get the stuff in the camera and that is just bad news.
If it works - Shoot away and have fun!
I get phone call threats for not paying my student loan (which I have never had one, nor has any of my kids - education was paid cash only). This is also a scam. Collectors will also send a letter and the IRS only sends letters to make appointments. I like the air horn idea, too.
I shoot the Tamron 18-270 as my general purpose lens on my Canon 7D and T5i. I do recommend this lens since it will cover your needs. I took the lens to Xian, China and photographed the Terracotta Soldiers with it, no flash. They keep the museum darker than normal to protect the original paint on the statues and those came out great. It is image stabilized, and that was needed for the longer exposures there. If your budget does not allow for the expensive lens, this is a great alternative.
I shoot the T5i, 7D, 5DII, XTi. One thing that comes to mind is to make sure that if you shooting in JPG, set your camera to Large Fine images. Sounds like you may be in the lowest resolution mode on the camera, which is what is set for out of the box.