That rear sprocket is running really high compared to the swingarm.
You probably need to get the front two tubes (the ones that run from the shock mounts through the upper control arm mounting bar and down to the lower frame rail straightened out and then cut the lower two tubes out and make a "drop down" section for that frame to get the chain aligned better.
Yeah, probably would have been better to go "down" with cutting the lower frame tubes than "up".
Also, the low bike bars will not cut it. I tried it and hit my knee on the throttle while turning. Quite exciting!
As far as longer swingarm and wider "A"arms, don't worry about that yet. If it is a lowered rig you may not even need it.
The extra weight down so low will also help with your stability.
Keep at it! Like it!