1. If not mistaken, there is no specific tenancy law to govern property lease, it is a private party contract between landlord and tenant.

2/3 Never paid in cash, unless you are getting a receipt that fully stated from whom and for what purposes upon paying the cash.
You have proper record by paying in cheque or bank transfer.
Some landlord may engage with property agent to manage their property, whereby they may request tenant to pay to agent, so be sure it is stated in the tenancy agreement. If not, the landlord may claim not receiving your rental if you are paying to agent. Also never pay to agent personal name, but agent company and be sure it is a registered property agent.

4. It is trust and contractual between landlord and tenant. You may point out that landlord has breached the contract by not repairing it through legal process but it is a hassle process, and may not worthwhile.
So it is more a trust between and sincerity between.

5. I know many may be doing this, but it is a breach of contract (tenancy agreement) by doing this.
Best to speak and discuss with the landlord.

SNP? 
or you mean tenancy agreement?

You can always view the detail of tenancy agreement before signing.
If not agreeing anything in the tenancy agreement, then discuss with landlord for revised term.
If can't then don't agree, don't sign then no deal.

Title is the one showing who is the owner, not SNP.

Alternative, one can perform search at land office, this is the most accurate and ultimate to show the actual owner.