Clarification on Cancellation Options

[GaryE]

My daughter is flying to Tenerife, via BA Holidays at the beginning of August and is dreading the likelihood of the email from BA that either or both her flights have been cancelled. Whilst not showing on BA list of cancelled flights the LHR to TFS flight has been cancelled every Thursday since the end of May. I know if given 14 days notices she and family are not entitled to compensation but only duty of care, but what are her options if either of the above happen. I know people on here say to do not cancel, or accept refund, or accept a different date as that gets the airline off their responsibilities, but with two young kids in tow that is easier said than done. So for the following scenarios what are her options:-
1. BA move her flight to an early morning or late evening on same day? – must she accept or can she ask to be re-routed on another airline which has a similar midday flight as hers (even from a different airport), arguing that it is inconvenient for two young children to be flying so early/late in the day ?
2. If the option they give her is a day earlier/or later to fly out and likewise to fly back – if it means going earlier or/and staying longer is it BA responsibility to put them up in their existing accommodation or similar accommodation for the extra nights?
3. If the option leaves them with a shorter holiday can they claim anything back from BA or can they insist that they wish to be rerouted both ways in order to have their full 11 day holiday?
Is there anything else she should consider if either/both of her flights get cancelled – based on current holiday pricing cancelling and rebooking with another operator does not look like an option!

Many thanks in advance for any assistance, as she wants to be forearmed with all the correct information in case any of the above happens.

[meta]

All these questions have been already answered via various threads. Could you please have a search and read since it is all hypothetical at the moment?

In short, you do not have to accept anything, but you have to be reasonable. Some things you will be able to claim from BA, some is for your travel insurance.