Visa problem

Dear Sir/Madam,

I hold a Hong Kong passport and I have been invited by the following parties to take a visit to London:
1 - My current company headquarter: to take a training; ("HQ Training") and
2 - an independent company (applying to be a registered sponsor): to take a trial work experience and discuss the potential to work for them in London ("Trial").
Both the HQ Training and Trial will only last for less than 3 months.

For the HQ training:
1: Do I need to apply for a work visa? Or a visitor visa is acceptable?
2: Is it fine for my salary to be paid by the London headquarter rather than my Hong Kong company during my training period? If not, can the London headquarter cover all of my expense, such as accommodation, travel and food, in London?
3: What supporting documents do I need to take with when I enter UK or applying a visa(if required)?

For the Trial:
1: What type of visa should I apply for?
2: Can the inviting company cover all of my expense, such as accommodation, travel and food, in London?
3: What supporting documents do I need to take with when I enter UK and applying a visa?

After the Trial, If I chose to accept the job offer (assuming they have register as a sponsor at that time). I will go back to Hong Kong and apply for a work visa.
1: I presume it will be a tier 2 general visa, right?
2: I notice that there are two systems named as the RQF and NQF. Which of them is effective right now? I am working as an investment manager and the independent company is a commercial property investment related company. Is such position qualify to apply for a tier 2 visa?
3: I have read news that the salary requirement for tier 2 visa has rise up to GBP 50,000 plus in order to get enough points. Is it true?


Thank you.

Regards
Steven

For the HQ training:
1: Do I need to apply for a work visa? Or a visitor visa is acceptable?
2: Is it fine for my salary to be paid by the London headquarter rather than my Hong Kong company during my training period? If not, can the London headquarter cover all of my expense, such as accommodation, travel and food, in London?
3: What supporting documents do I need to take with when I enter UK or applying a visa(if required)?

You cannot work in the UK on a visitor visa, either paid work, voluntary work or work where your expenses are paid.

For the Trial:
1: What type of visa should I apply for?
2: Can the inviting company cover all of my expense, such as accommodation, travel and food, in London?
3: What supporting documents do I need to take with when I enter UK and applying a visa?

I am not sure there is a visa for the purposes you want. You can only work on Tier 2 or some Tier 5 categories, both of which you need a sponsor as a Hong Kong citizen and for Tier 5 you can't be older than 30.

After the Trial, If I chose to accept the job offer (assuming they have register as a sponsor at that time). I will go back to Hong Kong and apply for a work visa.
1: I presume it will be a tier 2 general visa, right?
2: I notice that there are two systems named as the RQF and NQF. Which of them is effective right now? I am working as an investment manager and the independent company is a commercial property investment related company. Is such position qualify to apply for a tier 2 visa?
3: I have read news that the salary requirement for tier 2 visa has rise up to GBP 50,000 plus in order to get enough points. Is it true?

1. Correct.
2. You need to be RQF 6 to qualify for a Tier 2 General visa to get a RCoS. It depends on the SOC and job/job title you are potentially offered.
3. No it has not. You need to earn either £30,000 pa OR what the level stated in the SOC is, whichever HIGHER.

Business visa fits these purposes if there in any this sort-of visa available.