You can certainly use lead bullets in the Marlin.
Pretty much any SAAMI load will do well and be safe.
There is a difference in bore and groove sizes between MicroGroove and other styles of rifling - that's the point of MicroGroove.
Because the bore in MicroGroove rifling is slightly larger and the groove diameter is slightly smaller many common cast bullets for use in other firearms - such as most pistols - are not a good fit in the MicroGroove rifling and so may lead more and give inferior accuracy than bullets which do fit the Microgroove well. Bullets that fit the MicroGroove rifling may not fit other forms of rifling well and so the best bullets may not interchange across different firearms.
Just the same the answer is to try it.