the first one is 山峡之秋, not 乏
second is 春畝作. If it was calligraphy he would write 書. So this must be a painting.
and third 松田春畝
http://artisjapan.net/default.asp?action=1&num=2795
btw. that seal states something else than 春畝 (畝 maybe, but i cannot find corresponding form of 春 in seal script, tough, mind you, artis may have multiple pen names)
edit: oh wow, I found a corresponding form of 春 in seal script. So this is definitely his seal (春畝).
Here is the little devl:
By the way, this is a great opportunity to see how complex is the seal script.