Not Weaver Rails, I'm not sure
No it does not, however they are compatible.
It can be done. A lot of airsoft guns have rails systems which are based on Weaver or MIL-STD-1913 (Picatinny) rails, and Weaver scope bases can be used on these rails, the same as they could be on a real firearm.
No, the salvo had a picitanny rail, where the 98 has a custom slot.
The salvo has more accessories and has a better feed neck and stock then the Mr1.
The Project Salvo has Tippman 98 Custom barrel Threads.. Same with the Alpha black
there is picitiny an weaver are the main ones Save
Yes, all scopes that fit on the 7/8 rail will fit on the salvo.
unfortunately no it does not come with a hopper
On the ends of every barrel there are "threads" These are different for every series of guns. The Salvo marker has Tippmann threads therefore any Tippmann barrels can be use. Smart Parts also makes barrels for Tippmann markers. Actually the Project Salvo is a Tippmann 98 with a different body. It uses Tippmann 98 threads and any barrels that fits the 98 will fit the Salvo. The Salvo can use a A5 barrel if you add a 'A5 to 98′ adapter to convert the threads to the 98 style for your Salvo.
Since it has weaver rails, all you need are Weaver scope rings. An offset mount will help too.