Upvote:2
I recommend you read this question UK visa refusal on V 4.2 a + c (and sometimes 'e') and this Guide https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/827480/Visit-guidance-v9.0ext.pdf which should answer many of your questions.
A few things to bear in mind:
UKVI specifically advise against booking flights until the visa decision is known.
Do not send the person you are inviting money beforehand. ECO’s typically tend to view this as ‘funds parking’ (see the question I linked to above for a full explanation of this term).
the fact that you don’t have an income may count against you. Proportionality of intended spend to financial circumstances is important. Planning to spend a chunk of savings without a source of income may not be viewed as reasonable.
UK visitor visas are usually multi-entry but the holder will still need a visa to visit countries where their citizenship does not qualify them for visa-free entry. Applying for a visitor visa for Schengen, for example, must be done from the applicant’s country of residence.
Bank statements don’t need to be translated but all other documents must be in English or translated in accordance with the rules (see the Guide I linked to for more information).