1: Skipping would be as good and possibly better but the added height needed for the rope might not work in most basements- not mine anyway!
2: Again, a treadmill would be very useful but is expensive and again might not fit. it wouldn’t fit in ours and we were quoted some outrageous amount to sink an area in our floor to gain enough height for the treadmill- enough space for the tread and room for the motor to stay cool. for the amount we were quoted to drop the whole floor throughout, we could just train in Hawaii every winter for the next 20 years!
3: There is a limit to how much the sessions can prograss on the running end because of the possibility of shinsplints though you could move from the running to the bike work if you need more total volume. Of course after the indoor season you would progress from the basement work to tempo on any decent grass nearby once the weather improves.