Are UK visit visa approved if it’s refused once in the past?

I recently (3 weeks ago) applied to visit uk for leisure trip but due to reasons mentioned in the refusal letter, it was denied. I accept and agree to almost everything. The error was on my part as I didn’t submit relevant docs / proofs.

However, very soon my employer will sponsor me for an educational show (4-5 days) in London. In Jan 2017, I’d attended a similar educational conference/ show which was a 7 day visit. My employer sponsored for 6 employees for this visit and all of it was approved.

I would like to know - (1) if the fresh application with changed circumstances will have any good chances of getting an approval on another standard visit visa (with accurate and sufficient evidences provided)

(2) will this fresh application get affected due to my recent visa refusal?

Another option:

(3) if I plan another leisure trip but for only 15 days (unlike 11 weeks planned earlier), with an employment letter granting me paid leave right now, (as I’m actually entitled for 4weeks paid leave) and make a new application only for 15 days, without showing the details of my friends (since I won’t be with them this time). Will this strengthen my re-application? Or will ECO compare & doubt on the basis of older application?

Also note that I’ll apply for fresh application only after approx. 70days of the older one which was refused.

Since my application is genuine, I’m positive that ECO will be satisfied with the new application (either 4-5 days visit sponsored by employer OR my personal 15day trip) as I’ll provide all the appropriate evidences.