Ciatie,
To be honest the chances of you making a profit in the first few years is slim.
By the time you factor in mortgage interest, fixtures and fittings, maintenance costs, fees for letting, management fees etc. These are all yearly costs.
Add to that the initial costs of stamp duty, solicitor fees.
Think carefully and do the figures before jumping in and expecting to make a profit straight away.
In answear to your questions:
1) Doesn't really matter as your jointly assessed.
2) See above, I reckon for the first few years you will be carrying forward a loss.