Under TUPE, unless staff agree to something else, you are obliged to keep their main terms and conditions including pay. Hence salary, allowances etc will all transfer over. Therefore if someone if paid €5000 a month in their current role, they should also be paid that in the new company. An exception to that would be if you could not reasonably replicate a term, for example, bank staff often have an entitlement to discounted loans, in cases where they were outsourced to an IT company, that had to be bought out as the IT company could not replicate it. If that salary breaks your pay scales, to be brutal, that's your problem, not the staff members. In large multinationals who have taken over other companies or have taken on outsourcing deals, it would be quite common to have staff on different T&Cs
Service also comes accross, hence on day 1 working for you, if someone from the other company had worked for them for 10 years, they are deemed to have worked for you for 10 years. You need to bear that in mind if at any stage you are going to contemplate redundancies.
Pensions are not covered under TUPE, normally staff would leave their existing pension scheme and be given the option of joining your company scheme and potentially transferring the fund in the old scheme into yours
Note there is nothing to stop you offering your new employees contracts with your T&Cs on it, however they are not obliged to sign them, and even if they do, their service will still carry over