In terms of asking professors to submit multiple recommendations - if you know how many you need, then I would certainly disclose that number to them as you are asking. But with the invention of the online submission form in the Applyyourself system, this should not be a hardship - you write a recommendation letter, then upload it into the system. Once the letter is written, ten uploads will take about ten minutes. I shouldn't think it would be a problem. If it is, then they should tell you so when you request the recommendation.
In terms of who to ask for the rec- you should always ask for a recommendation from the professors who are most able to speak to your strengths as a scholar. I can assure you that a detailed, thorough recommendation from an assistant professor will carry more weight with an adcomm than a rec from, say, J.R.R. Tolkien, Professor Emeritus in English at Oxford, that says "Janey is a fantastic student. I recommend her fully for your program. Sincerely, J.R.R. Tolkien." Unless a big-name professor has specific ties with the department in question and/or has a track record of only sending really great applicants, that rec is pretty much useless - remember, s/he who is well-known in your field may be just another member of the MLA to people on the adcomm. You my be a medievalist who knows and adores Larry Benson's work; the adcomm may be comprised of 17th, 18th, and 20th century American studies professors. That's why letters of recommendation should speak to your strengths across the board as an English student, as specifically as possible.
Now, if you could get the above-mentioned Tolkien to write you a one page evaluation of you as a super-promising linguist and an extremely strnong reader with a penchant for comparative work, then THAT letter would definitely be the one to get (not to mention, involving an inexplicable instance of time-travel, but I digress...)! But in your situation, it seems your better choice is going to be the second professor. You have taken more classes with him/her, and therefore s/he is more familiar with you as a student.