Vela as done well in Spain and I mentioned him as a signing last summer.
Bacca is another player from la liga who's done well domestically and in Europe this season and at less than £10m is worth looking at IMO.
It's not entirely clear what Remy's buy out clause is but if it's around £10-12m then he's worth a serious look at this summer aswell.
Same with likes of Drmic (£4.5m buy out clause) & Batshuayi (just short of £7m buy out clause), young talented strikers doing well in there respected leagues and cos of the price are worth taking a gamble on I reckon.
I've seen us, Liverpool & Arsenal linked to Lacazette of Lyon recently for around £10m and he'd be a cracking signing. Very Henry like IMO in style and although he's a striker he can play in the No.10 role, aswell as wide.
I really don't think we'll sign Lukaku now, not without CL and not for £20m or more as we're not cash rich and without the finances the CL can bring we can't afford to fork out £20m+ soley on one player, not even if the down payment was £15m plus add ons! And as much as I'd like us to be in for Bony I don't think we could afford to spend a large sum on him either.
So I can see us going for one of the other strikers above, possibly Remy. But don't be too surprised if we went back in for Ba this summer, don't forget, Martinez wanted to sign him originally before being offered Lukaku on loan, and you'd imagine he'll be available this next window?!