Sakho is our best defender why would we want to sell him?!? For me Agger is the most likely to go from the three of them.
Playing football manager

I'd do the following:-
Sell:- Agger £7m, Aspas £2m, Assaidi £1m, Borini £8m plus other youth players £2m so a total of £20m on top of the £60m (budget plus CL money) giving us £80m.
In:-
Well a left back for me is a priority I'd target a number of left backs that are attainable to us:- Ricardo Rodriguez from Wolfsberg, De Sciglio at Milan, Ansaldi at Zenit, Ben Davies at Swansea. Hell I'd even offer Ashley Cole a 1 year deal.
My dream signing would be De Sciglio but imo he wouldn't leave Milan for another couple of years. My next preference would be Rodriguez.
For me Luke Shaw is unattainable. He is Chelsea bound imo.
So I'd say £15m for Rodriguez or Davies. Argument sake say Rodriguez.
I'd spend £10m or so plus a couple of youth players on loan for Caulker. I've been impressed by him since his Swansea days on loan and Spurs were mad to sell him. Brendan knows him well and would be a good signing for us I think.
I'd then spend £18m on Konoplyanka as we need further options in offensive positions.
I'd try and get Ivan Rakitic from Southampton. I'd offer them £20-25m for him. He'd compete well with Gerrard, Lucas, Allen and Henderson for a place in midfield and give us further depth in that area.
I'd then target a back up striker as I've sold Borini and Aspas. I'd target one of Bony, Cardozo, Vucinic, Rodriguez, Remy. I'd attempt to get Remy and offer QPR £15m.
Priority is definitely the full back position but perversely we have extremely strong back ups in those areas in Flanagan and Enrique. Ricardo Rodriguez has many suitors though and can pick his next club so may be out of our price range. Ben Davies is a player I think can be a good job for us and has the potential to be much better too.
I would like to keep Borini in the squad for next season however I think after hearing the rumors I think he is going. We definitely need a quality back up for the SAS next season especially as we should be in europe. Remy has been excellent for Newcy and doubt he'll want to stay there or go back to QPR and if we have CL football we should attract him to us as there will be many clubs who'd want him. Were we to miss out on him then I'd target Bony who I think is top class but Swansea will hold us to ransom. Cardozo would offer us experience and wouldn't demand first team football. Same with Vucinic. A striker who I really fancy and don't know really why but I think has natural talent and physical prowess is Jay Rodriguez. Always been impressed by him whenever I've seen him play and have good link up skills, great physical assets and great finishing.
I also believe we need another body in midfield. Gerrard and Lucas have the DM position sewn up but we need another midfielder to help out Henderson and Allen and provide us with something different. Last two transfer windows we've been linked with Rakitic. I'd love to sign him as I think he's a really dynamic midfielder and would give us something different plus he has power. Alas many clubs would want him so we may be priced out. If so then I'd love to sign Morgan Schneiderlin from Southampton. Vastly underrated player and would give us those abilities Rakitic possesses but at a slightly lower level but never the less would be a superb signing.
Brendan obviously wants another goal scoring wide man. Having targeted Willian, Salah, Konoplyanka etc. I think we'll be in for Konoplyanka again and with CL football we should get him.
So that would be Rodriguez, Caulker, Rakitic, Konoplyanka and Remy in my squad.
So my squad would be:-
GK:- Mignolet, Jones
RB:- Johnson, Flanagan, Wisdom, Kelly
LB:- Rodriguez, Enrique, Smith
CB:- Sakho, Skrtel, Caulker, Toure, Ilori
DM:- Gerrard, Lucas
CM:- Allen, Henderson, Rakitic, Rossiter, Lussey
AM:- Coutinho, Suso, Teixeira,
FD:- Suarez, Sturridge, Konoplyanka, Remy, Sterling, Luis Alberto,
Excuse my indulgence into football manager mode haha!!