The MS lounge in CAI is very small, like 20 persons capacity

I checked that before getting our flight CAI-LHR - because BA also uses MS lounge at CAI.  People of both Star Alliance and of course OneWorld on BA, have endless complaints on the very poorly equipped lounge. 

For your overnight at Abu Simbel,  surely there are providers cater for that, and also want an arm and a leg from those who want to have the "experiences".   Go to either Viator or TripAdvisor, search Abu Simbel Sound and Light Show - you will find at least 1/2 a doz or more providers on such.

My opinion on traveling in 3rd world countries, is that extra services that normally you do not need, are wellworth to spend on, because doing so would avoid lots and lots of nuiances / annoyances / frustrations.  Sure, one can still do be the true and true DIY person but NOT worth the hassles in 3rd world countries!  

For that matter, using pre-reserved online transportation service would be quite a bit more than getting a local taxi.  But then you dont have to haggle with the local taxi drivers, who 10 out of 10 would tell you the meters do not work.  You then negotiate the fare with him until one is willing to take your fare...  I dont want to be on the street outside the hotel or the sight, spend 10, 15 min haggling with each taxi driver who would stop and then got one you two come to an agreement.   What a waste of the traveller's time and energy on such haggling.  YMMV naturally. 

I firmly believe services that have a clearly stated price tags, and from reliable providers, are well worth the extra EGPs paid over whatever the EGP cash you eventually agreed after the haggling.  You can try Uber or the local Uber but it depends on the traffic, they are not very reliable.  The advantage is, your app will be in English so supposedly no language barrier.  For us, the ONLY transportation we would need in Cairo is the last day from hotel to CAI.  Everything else, is incl in the tour package.  In Luxor where we stay for 3 nights, we may need taxi in the evening if we want to wonder out further.  The hotel Misr used, is quite close to town center,  versus Hilton resort which is at the North of town center.  Hence we opted to let Misr take care of the hotel in Luxor while we book the hotels in Cairo ourselves.

Besides, the services in Egypt are fairly cheap.  What are expensive, especially when considering the income levels of the locals,  are the meal costs in tourist towns like Luxor and Aswan, especially Luxor.  That is unavoidable,  so be it.