Camera Upgrade Suggestions!

Hello NS! I am looking for a new camera body to upgrade my current setup and was looking for suggestions. I went ahead and copied and pasted the questions from the "what camera" thread:
1) What is your budget? How much money can you spend right away, and do you think you can get more money to invest in the future?

My budget for body only is around $1,500. I might be able to stretch that out a bit, but I'm also saving for other things.

2) What experience do you already have with cameras? Have you ever even used one before? Have you helped your friend out with his camera? Have you owned your own?

I have about a year of on and off camera experience mostly from borrowing my sister's/school's gear, and I was recently gifted a T3i in November. I shoot in full manual, other than autofocus and my sister is a professional photographer who shares her advice and tips with me. I have also taken a photography course in highschool. Here's some of my work over the last few months (most of it is from the past week). I have been told I am "talented/fast learner".

2) What gear, if any, do you currently have? (tripod, old camera lenses, mics, etc)

I currently have a Rebel T3i with the kit lens (18-55mm), a 50mm f/1.8, and a 70-300mm f/4 IS, however I have experience with a Canon 70d body, 24-70mm f/2.8 lens, 70-200mm f/2.8 II IS, 100mm f/2.8 and 50mm f/1.4 and also a 35mm Pentax Spotmatic with a 50mm lens. My other gear that I currently have is an old tripod my parents gave me, a Takstar SGC-598 microphone, wide angle lens adapters and extension tubes.

4) What are you planning to shoot and how do you want to use your camera? Are you going to use this with the sole purpose of shooting skiing? or do you think you might try other stuff as well (movies, documentaries, short films, etc)

I plan to use this camera for about 25% filming skiing, 10% filming little short films and cinematography/lifestyle/etc videos, and 65% for photography (I shoot basically everything: night, urban, landscape, portrait, skiing/action, etc.)

5) Do you want a camera that you can hand to your friends, that could or could not have film experience, and let them shoot you? or will you be doing all the filming?

I would do most of the filming, but some of my pretty un-knowledgeable friends would shoot me as well, but I usually set everything up for them before they film.

6) When filming skiing, how do you tend to shoot? (follow cams, leave it on record on a tripod and hike, film from a tripod, etc)

I usually do follow cams and tripod shots. Most follow cams for park, with some tripod shots, and mostly tripod shots for big mountain.

7) What computer do you currently have/use to edit (if not currently editing, what would you most likely use)? If you can provide specifics, such as hard drive space, RAM, processor size, that would be great.

I currently have a Acer Aspire F 15 laptop, with 1tb of hard drive space, 12gb DDR4 RAM, i7-6500U 2.5GHz (up to 3.1GHz) processor, and a Intel HD Graphics 520 card with up to 6208 MB of Dynamic Video Memory.

7) What program do you currently edit on? How familiar are you with it (1- just learning; 10- I can make tutorials and know the keyboard layout)

I have Adobe Lightroom 6 for photography (I am about 7/10 familiar with it) and Sony Vegas Pro 14 (about 6/10 familiar with it).

I'm completely open to any suggestions!

I just have one question about switching to a camera with a different lens mount than my current setup: obviously I would either have to get an adapter for my current lenses, or just buy new lenses which would be really pricey... I would like to know the downsides (if any) of using a lens mount adapter (does it affect image quality, camera settings, lens settings, lens errors).

Thanks again NS! Stoked to see some suggestions!