Hi Zoe,
If I'm being honest, hiring an 'expert' or 'professional' is extreme & is probably only feasible where records you need have to be looked up in person but sometimes people on here are willing to help in that way.
I would suggest you post the info. you have here relating to the people who moved to Scotland (providing they are likely to be deceased).
Names (including middle names) of all who you know came to Scotland
Birth dates
Where born (this helps for census') as sometimes place names are mentioned not just Ireland
Occupations
Parents names with mother's maiden name
Possible place name of where they were in Scotland if known?
If place is known but spelling not known, post (soundex) & we can try & work out where it is?
When they moved or at least possibly when?
Anything you know about their time in Scotland.
There are many good researchers on here, all willing to help & where records are required from the government site & available, help is at hand to guide you with use of scotlandspeople.gov.uk which is a pay-per-view site at very reasonable cost via credits.
If you are unfamiliar with the site there are many who can look up possible info. from the free index & other means for you.
It may be worth joining (which is free) to acquaint yourself with the site as you only pay for downloads but you can find names/addresses/wills for potentials all free on the indexes.
Married woman are recorded on death with both marital & maiden surnames which is a huge bonus (providing the informant knew the details) as with any death & another bonus is both parents are named on any Scottish marriage or death too (if known by informant).
Look forward to you posting the details

Annie